If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Opteron - single dual core vs two single cores
Hi, I'm about to buy a workstation, and wonder what the functional
difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? Thanks very much...... |
#2
|
|||
|
|||
Opteron - single dual core vs two single cores
In article . com,
"CharlesBlackstone" wrote: Hi, I'm about to buy a workstation, and wonder what the functional difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? Thanks very much...... Two single-cores versus a dual co http://www.geek.com/news/geeknews/20...1108033166.htm Benchmarks start on page 10: http://www.tomshardware.com/2005/11/...le/page10.html The advantage of two single core processors, is the number of chipset chips on the motherboard. The AMD processor is a "hub" with Hypertransport busses sprouting out of it. With two single cores, you can have two true PCI Express X16 slots, plus lots of tunnels for peripheral busses. If there is only one CPU socket on a motherboard, generally the I/O features are a bit less (they don't have to be, but companies don't generally use large numbers of daisy chained tunnel chips). This is mostly related to motherboard marketing, and the proposed uses for single socket versus dual socket systems (workstation versus server perhaps). Example block diagram on page 2, of a dual socket board: ftp://ftp.tyan.com/datasheets/d_s2895_100.pdf Note that if the "H0" socket is not occupied by a processor, you lose the use of a PCI Express x16 slot, an ethernet interface, and the use of four more DIMM slots. The board will still work with just one processor (single or dual core) in socket "H1". If you buy a motherboard with a single socket, well, you never have to worry about this, but you also have fewer facilities of all sorts on the motherboard. If your box is a pure compute engine, and the only peripheral you have is a USB socket for your Ipod, the single socket dual core processor wins. If the box is intended to hold a wealth of hardware, then using two sockets might be a better answer, even if it is computationally slightly slower. With two sockets, you have two memory controllers, and you would think, more memory bandwidth. A single socket setup has access to fewer total sticks of RAM, which might be important consideration if the problems you handle need a lot of RAM. "Cache-Coherent Nonuniform Memory Access (ccNUMA)" - the theory http://cdrom.amd.com/21860/updates/B...elp-09-04.html "Non-Uniform Memory Architecture (NUMA): Dual Processor AMD Opteron Platform Analysis" - benchmarks (Conclusion - set node interleave off ; use "numa aware" OS) http://www.digit-life.com/articles2/cpu/rmma-numa.html That last article shows that you can get 12.8GB/sec memory bandwidth, as long as each single core processor only accesses its own local memory at 6.4GB/sec. While the dual socket system has the ability to use any memory by either processor, there is a penalty associated with going to the "other" memory. If your system has ECC memory, I think features like scrubbing and the like, may also affect whether things like node interleave can be turned on. Dual sockets have their complexities, as do setting up dual core processors. For the chunk of cash you'll be paying for either system, I hope the person setting it up does a good job. Paul |
#3
|
|||
|
|||
Opteron - single dual core vs two single cores
On Sat, 05 Aug 2006 15:06:34 -0700, CharlesBlackstone wrote:
Hi, I'm about to buy a workstation, and wonder what the functional difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? For workstations, 1 core per socket is kinda dead. Go for the dual-core. The X2's just came down, a lot. Besides, I don't believe AMD is selling 940-pin single core Opterons anymore, anyway. |
#4
|
|||
|
|||
Opteron - single dual core vs two single cores
Paul wrote: In article . com, "CharlesBlackstone" wrote: Hi, I'm about to buy a workstation, and wonder what the functional difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? Thanks very much...... Two single-cores versus a dual co http://www.geek.com/news/geeknews/20...1108033166.htm Benchmarks start on page 10: http://www.tomshardware.com/2005/11/...le/page10.html The advantage of two single core processors, is the number of chipset chips on the motherboard. The AMD processor is a "hub" with Hypertransport busses sprouting out of it. With two single cores, you can have two true PCI Express X16 slots, plus lots of tunnels for peripheral busses. If there is only one CPU socket on a motherboard, generally the I/O features are a bit less (they don't have to be, but companies don't generally use large numbers of daisy chained tunnel chips). This is mostly related to motherboard marketing, and the proposed uses for single socket versus dual socket systems (workstation versus server perhaps). Example block diagram on page 2, of a dual socket board: ftp://ftp.tyan.com/datasheets/d_s2895_100.pdf Note that if the "H0" socket is not occupied by a processor, you lose the use of a PCI Express x16 slot, an ethernet interface, and the use of four more DIMM slots. The board will still work with just one processor (single or dual core) in socket "H1". If you buy a motherboard with a single socket, well, you never have to worry about this, but you also have fewer facilities of all sorts on the motherboard. If your box is a pure compute engine, and the only peripheral you have is a USB socket for your Ipod, the single socket dual core processor wins. If the box is intended to hold a wealth of hardware, then using two sockets might be a better answer, even if it is computationally slightly slower. With two sockets, you have two memory controllers, and you would think, more memory bandwidth. A single socket setup has access to fewer total sticks of RAM, which might be important consideration if the problems you handle need a lot of RAM. "Cache-Coherent Nonuniform Memory Access (ccNUMA)" - the theory http://cdrom.amd.com/21860/updates/B...elp-09-04.html "Non-Uniform Memory Architecture (NUMA): Dual Processor AMD Opteron Platform Analysis" - benchmarks (Conclusion - set node interleave off ; use "numa aware" OS) http://www.digit-life.com/articles2/cpu/rmma-numa.html That last article shows that you can get 12.8GB/sec memory bandwidth, as long as each single core processor only accesses its own local memory at 6.4GB/sec. While the dual socket system has the ability to use any memory by either processor, there is a penalty associated with going to the "other" memory. If your system has ECC memory, I think features like scrubbing and the like, may also affect whether things like node interleave can be turned on. Dual sockets have their complexities, as do setting up dual core processors. For the chunk of cash you'll be paying for either system, I hope the person setting it up does a good job. Paul Paul, many, many thanks for your excellent answer. I sure appreciate it... JK |
#5
|
|||
|
|||
Opteron - single dual core vs two single cores
Paul wrote: In article . com, "CharlesBlackstone" wrote: Hi, I'm about to buy a workstation, and wonder what the functional difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? Thanks very much...... Two single-cores versus a dual co http://www.geek.com/news/geeknews/20...1108033166.htm Benchmarks start on page 10: http://www.tomshardware.com/2005/11/...le/page10.html The advantage of two single core processors, is the number of chipset chips on the motherboard. The AMD processor is a "hub" with Hypertransport busses sprouting out of it. With two single cores, you can have two true PCI Express X16 slots, plus lots of tunnels for peripheral busses. If there is only one CPU socket on a motherboard, generally the I/O features are a bit less (they don't have to be, but companies don't generally use large numbers of daisy chained tunnel chips). This is mostly related to motherboard marketing, and the proposed uses for single socket versus dual socket systems (workstation versus server perhaps). Example block diagram on page 2, of a dual socket board: ftp://ftp.tyan.com/datasheets/d_s2895_100.pdf Note that if the "H0" socket is not occupied by a processor, you lose the use of a PCI Express x16 slot, an ethernet interface, and the use of four more DIMM slots. The board will still work with just one processor (single or dual core) in socket "H1". If you buy a motherboard with a single socket, well, you never have to worry about this, but you also have fewer facilities of all sorts on the motherboard. If your box is a pure compute engine, and the only peripheral you have is a USB socket for your Ipod, the single socket dual core processor wins. If the box is intended to hold a wealth of hardware, then using two sockets might be a better answer, even if it is computationally slightly slower. With two sockets, you have two memory controllers, and you would think, more memory bandwidth. A single socket setup has access to fewer total sticks of RAM, which might be important consideration if the problems you handle need a lot of RAM. "Cache-Coherent Nonuniform Memory Access (ccNUMA)" - the theory http://cdrom.amd.com/21860/updates/B...elp-09-04.html "Non-Uniform Memory Architecture (NUMA): Dual Processor AMD Opteron Platform Analysis" - benchmarks (Conclusion - set node interleave off ; use "numa aware" OS) http://www.digit-life.com/articles2/cpu/rmma-numa.html That last article shows that you can get 12.8GB/sec memory bandwidth, as long as each single core processor only accesses its own local memory at 6.4GB/sec. While the dual socket system has the ability to use any memory by either processor, there is a penalty associated with going to the "other" memory. If your system has ECC memory, I think features like scrubbing and the like, may also affect whether things like node interleave can be turned on. Dual sockets have their complexities, as do setting up dual core processors. For the chunk of cash you'll be paying for either system, I hope the person setting it up does a good job. Paul Paul, many, many thanks for your excellent answer. I sure appreciate it... JK |
#6
|
|||
|
|||
Opteron - single dual core vs two single cores
Douglas Bollinger wrote:
Besides, I don't believe AMD is selling 940-pin single core Opterons anymore, anyway. wrong AMD 940 Opteron single core; Newegg prices: same speed dual core (all 90nm (all free)) today(shipping) today 3-31-2006(shipping) 246/90nm/oem $159.99(free) $162.00(+$3.99) 2.0GHz 246/90nm/retail $185.00(free) $180.00(+$3.99) 2.0GHz 270/$498.00 $476.00(+$3.99) 248/120nm/retail $223.00(free) $237.50(+$.99)/120nm 2.2GHz 275/$699.99 $689.00(+$3.99) 250/90nm/retail $339.00(free) $339.00(+$.99) 2.4GHz 280/$869.00 $919.00(+$3.99) 252/90nm/retail $468.00(free) $461.00(+$3.99) 2.6GHz 285/$1,065 N/A 254/90nm/retail $689.00(free) $691.00(+$3.99) 2.8GHz i also see, at Newegg today, that all 3 Xeon Woodcrest CPUs that they offer, are out of stock when those Woodcrest CPUs are in stock is when AMD may have to adjust pricing on their 940 Opteron CPUs the open question is: how long before that happens? bill |
#7
|
|||
|
|||
Opteron - single dual core vs two single cores
On 5 Aug 2006 15:06:34 -0700, "CharlesBlackstone"
wrote: Hi, I'm about to buy a workstation, and wonder what the functional difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? There are some differences between the two, the biggest being that with a single dual-core processor you have all your memory hanging off one memory controller while a pair of single-core chips each have memory hanging off their own memory controllers. The advantage/disadvantage here is that with the one dual-core chip you can run with only 2 DIMMs but are limited to a maximum of 4 or 8 DIMMs (depending on the board), while with the two single-core chips you want a minimum of 4 DIMMs but can expand up to 8 or 16 DIMMs. Therefore, if you're application needs lots of memory (8GB+) a pair of single-core chips is processors might be better. Another difference is that the single-core chips usually have one clock speed above the fastest dual-core chips. For example, right now the fastest dual-core Opteron is the 285, which runs at 2.6GHz. The fastest single-core Opteron is the 254 which runs at 2.8GHz. In terms of performance, there are a handful of pluses and minuses on either side. Two processors, each with their own memory controller, give you more theoretical bandwidth. The downside is that you now have a NUMA setup with half your memory being remote and therefore suffering a latency penalty. Cache access also can suffer a bit of a latency penalty as accessing the cache on a second core in a dual-core chip is much faster then accessing cache on a physically different chip in a dual-processor setup. In the end though, the performance differences mostly get lost in the noise. A single dual-core chip will usually come out on top, but not by any big margin. The *REAL* difference in all this is cost. A one-socket motherboard and a single dual-core chip will be a fair bit cheaper than a 2P motherboard with a pair of single-core chips. This is especially true if you opt for a dual-core Athlon64 X2 vs. a pair of single-core Opteron chips. Even though the X2 chips are marketed as desktop chips they could make for quite a good workstation setup with the right motherboard. Only possible shortfall here is that unbuffered ECC memory is a bit rare, so if error correction is required for your workstation you might need to do a bit of digging. ------------- Tony Hill hilla underscore 20 at yahoo dot ca |
#8
|
|||
|
|||
Opteron - single dual core vs two single cores
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1 In article , Tony Hill wrote: There are some differences between the two, the biggest being that with a single dual-core processor you have all your memory hanging off one memory controller while a pair of single-core chips each have memory hanging off their own memory controllers. OTOH, the two cores in a dual-core processor have equal access to memory. In a dual-processor system with memory attached to one processor, processor #2 will have to go through processor #1 to access memory. The dual-Opteron at which I'm typing this message is set up that way, with a couple of 512-MB DIMMs hanging off one processor. Prime95 running on processor #2 takes noticeably longer per iteration than Prime95 running on processor #1. (I'd provide numbers, but they're currently doing different types of work (one is factoring and the other is LL-testing).) Putting memory on both processors would fix this, but that would be an additional expense you would want to keep in mind. _/_ / v \ Scott Alfter (remove the obvious to send mail) (IIGS( http://alfter.us/ Top-posting! \_^_/ rm -rf /bin/laden What's the most annoying thing on Usenet? -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) iD8DBQFE2icwVgTKos01OwkRAtJcAKDggnrlJqP9Pur4R+Je3S NPVAQC+gCgvAD5 nRYA8cUy2xoOc+dXdrZ7v9I= =xCHb -----END PGP SIGNATURE----- |
#9
|
|||
|
|||
Opteron - single dual core vs two single cores
On Wed, 09 Aug 2006 00:13:11 -0400, Tony Hill
wrote: On 5 Aug 2006 15:06:34 -0700, "CharlesBlackstone" wrote: Hi, I'm about to buy a workstation, and wonder what the functional difference would be between getting a machine with two single-core processors, and a machine with one dual-core processor? Is it essentially the same thing, or are the two single-cores more independent in terms of function, memory access, etc. that would affect overall performance? There are some differences between the two, the biggest being that with a single dual-core processor you have all your memory hanging off one memory controller while a pair of single-core chips each have memory hanging off their own memory controllers. The advantage/disadvantage here is that with the one dual-core chip you can run with only 2 DIMMs but are limited to a maximum of 4 or 8 DIMMs (depending on the board), while with the two single-core chips you want a minimum of 4 DIMMs but can expand up to 8 or 16 DIMMs. Therefore, if you're application needs lots of memory (8GB+) a pair of single-core chips is processors might be better. Another difference is that the single-core chips usually have one clock speed above the fastest dual-core chips. For example, right now the fastest dual-core Opteron is the 285, which runs at 2.6GHz. The fastest single-core Opteron is the 254 which runs at 2.8GHz. In terms of performance, there are a handful of pluses and minuses on either side. Two processors, each with their own memory controller, give you more theoretical bandwidth. The downside is that you now have a NUMA setup with half your memory being remote and therefore suffering a latency penalty. Cache access also can suffer a bit of a latency penalty as accessing the cache on a second core in a dual-core chip is much faster then accessing cache on a physically different chip in a dual-processor setup. In the end though, the performance differences mostly get lost in the noise. A single dual-core chip will usually come out on top, but not by any big margin. The *REAL* difference in all this is cost. A one-socket motherboard and a single dual-core chip will be a fair bit cheaper than a 2P motherboard with a pair of single-core chips. This is especially true if you opt for a dual-core Athlon64 X2 vs. a pair of single-core Opteron chips. Even though the X2 chips are marketed as desktop chips they could make for quite a good workstation setup with the right motherboard. Only possible shortfall here is that unbuffered ECC memory is a bit rare, so if error correction is required for your workstation you might need to do a bit of digging. I didn't have any trouble getting unbuffered ECC DDR a few weeks ago and yes a system like that makes a nice workstation or Intranet Web/ASP server -- my purpose -- for not a lot of money. Funny, Crucial doesn't list the 2GB kit I got in their DDR listings but looking up the mbrd, an Asus A8N-E, still shows it as available; for DDR2, they show it in the PC-5300 stuff *but* at 3x the price of the DDR!!... which makes s939 still an attractive bet, to me anyway. Of course you won't find it in the "boutique" lines which cater to the OC/gamer market and which many on-line vendors also seem to concentrate on. Oh and BTW I can find nothing on ECC reporting so who knows if it really works... whats new??:-) -- Rgds, George Macdonald |
#10
|
|||
|
|||
Opteron - single dual core vs two single cores
"Tony Hill" wrote in message
[...] In the end though, the performance differences mostly get lost in the noise. A single dual-core chip will usually come out on top, but not by any big margin. The *REAL* difference in all this is cost. A one-socket motherboard and a single dual-core chip will be a fair bit cheaper than a 2P motherboard with a pair of single-core chips. You also need to factor in commercial OS licencing. MS views dual-core as a single CPU for licencing purposes. You pay more to licence Windows on 2 CPUs. |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
got a dual opteron, single core, but.. | Henrik Tived | AMD x86-64 Processors | 2 | July 30th 06 04:57 PM |
Another dual core vs. single query | MZB | Dell Computers | 13 | July 17th 06 10:09 AM |
AMD X2 Dual Core 3800. How many different cores does this chip have ? | Paul Mathews | Homebuilt PC's | 1 | November 24th 05 03:28 PM |
Are dual core CPUs worth it? | Random Person | General | 20 | September 2nd 05 09:10 PM |
Dual CPU systems - still worth it? | Mr. Grinch | Overclocking AMD Processors | 9 | May 2nd 04 09:02 AM |