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PII vs PIII
It looks like the machine I have (an HP Kayak XAS, you may have seen me mention it already) can be upgraded from a PII 400MHz to dual PIII 600MHz. But the PIII's are substantially more expensive than the PII's, around $70 each compared to $10 each. I guess I'm not that excited about a 50% increase in clock rate, by itself. But is there a great advantage just in going from a PII to a PIII with a comparable clock speed? Would I get substantially more computing for the money? -- "Is that plutonium on your gums?" "Shut up and kiss me!" -- Marge and Homer Simpson |
It looks like the machine I have (an HP Kayak XAS, you may have seen me
mention it already) can be upgraded from a PII 400MHz to dual PIII 600MHz. But the PIII's are substantially more expensive than the PII's, around $70 each compared to $10 each. I guess I'm not that excited about a 50% increase in clock rate, by itself. But is there a great advantage just in going from a PII to a PIII with a comparable clock speed? Would I get substantially more computing for the money? There *can* be an advantage, but whether it's important to you is debatable. Early P3's had the same cache architecture as the P2's - namely, external cache running at half of the CPU's clock speed. Starting around the 600 MHz mark, you were able to get P3's with on-die cache running at full CPU speed. So, if cache latency is a deal-breaker for your application, the extra money would be worth it. If not, then it's a lot more of a personal-preference type of thing. As a side note, I'm surprised that a P3/600 would be $70, seeing that you can buy something like an Athlon 2400+ for less than that. I looked over on ebay, and found the P3's running $20 to $30 each. steve |
In article ,
Steve Wolfe wrote: It looks like the machine I have (an HP Kayak XAS, you may have seen me mention it already) can be upgraded from a PII 400MHz to dual PIII 600MHz. But the PIII's are substantially more expensive than the PII's, around $70 each compared to $10 each. I guess I'm not that excited about a 50% increase in clock rate, by itself. But is there a great advantage just in going from a PII to a PIII with a comparable clock speed? Would I get substantially more computing for the money? There *can* be an advantage, but whether it's important to you is debatable. Early P3's had the same cache architecture as the P2's - namely, external cache running at half of the CPU's clock speed. Starting around the 600 MHz mark, you were able to get P3's with on-die cache running at full CPU speed. So, if cache latency is a deal-breaker for your application, the extra money would be worth it. If not, then it's a lot more of a personal-preference type of thing. As a side note, I'm surprised that a P3/600 would be $70, seeing that you can buy something like an Athlon 2400+ for less than that. I looked over on ebay, and found the P3's running $20 to $30 each. There's a wide range of prices, so I tried to generalize, and I was looking specifically at PIII 600MHz 512 cache. I was thinking especially of a matched pair I saw for something over $100, although they had 256K cache. I suppose I should make sure I can get the system up and running in the first place, before I start worrying about upgrading it. I'm still waiting for some cables and adapters to arrive so I can plug it into my monitor, so I still can't see what I'm doing and it's just sitting there with a clean hard drive right now. -- "Is that plutonium on your gums?" "Shut up and kiss me!" -- Marge and Homer Simpson |
When Intel went to the on chip L2 cache it was not to increase performance, it was to save money. They cut the size of the cache from 512 Kb to 256 Kb. My old Pentium 2 L2 cache tested at half of the L1 cache speed, which it is supposed to be. With my Pentium 3 (1.26 Ghz with 512 Kb L2 cache) the L2 cache tests at 60% of L1 cache speed, not 100% as Intel would have you believe. Steve Wolfe wrote: There *can* be an advantage, but whether it's important to you is debatable. Early P3's had the same cache architecture as the P2's - namely, external cache running at half of the CPU's clock speed. Starting around the 600 MHz mark, you were able to get P3's with on-die cache running at full CPU speed. -- Mike Walsh West Palm Beach, Florida, U.S.A. |
On Fri, 10 Oct 2003 17:34:03 UTC in comp.os.linux.hardware,
(Gregory L. Hansen) wrote: There's a wide range of prices, so I tried to generalize, and I was looking specifically at PIII 600MHz 512 cache. I was thinking especially of a matched pair I saw for something over $100, although they had 256K cache. The fact that the top speed for this board is 600MHz leads me to think that it will only work with the "Katmai" flavour of P-III not with its successor the "coppermine". The Coppermine was the one where they halved the amount of L2 cache on the basis that they made it full speed at the same time. These chips require a lower core voltage than the Katmai ones and some motherboards don't have voltage regulators that are capable of supplying the correct one. So, if it says top speed is 600MHz they probably mean that you're limited to the older, 512KB cache, P-III's. -- Trevor Hemsley, Brighton, UK. |
The fact that the top speed for this board is 600MHz leads me to think
that it will only work with the "Katmai" flavour of P-III not with its successor the "coppermine". The Coppermine was the one where they halved the amount of L2 cache on the basis that they made it full speed at the same time. These chips require a lower core voltage than the Katmai ones and some motherboards don't have voltage regulators that are capable of supplying the correct one. So, if it says top speed is 600MHz they probably mean that you're limited to the older, 512KB cache, P-III's. It still might pay to check if it will support them or not - there are a number of boards which were originally designed for P2's which also had the flexibility to support the P3 Coppermines - my home machine, with a 650 MHz P3, is running on such a motherboard. steve |
When Intel went to the on chip L2 cache it was not to increase
performance, it was to save money. They cut the size of the cache from 512 Kb to 256 Kb. My old Pentium 2 L2 cache tested at half of the L1 cache speed, which it is supposed to be. With my Pentium 3 (1.26 Ghz with 512 Kb L2 cache) the L2 cache tests at 60% of L1 cache speed, not 100% as Intel would have you believe. The *frequency* at which the cache works in the on-die chips is actually 100% of clock speed. However, as you point out, that doesn't work out to 100% performance, as there are a lot of factors involved. However, in apps where cache latency is a factor, the chips with on-die cache do come out ahead. Perhaps the largest limitation to the P3 line is it's limitted FSB, at 133 MHz. I've used a good number of dual-p3 servers, and found that once the CPU gets up to about 866, you've got pretty much all the performance you're going to get - a faster CPU doesn't do anything for you. Once you start talking about the "-S" chips (the later P3's with 512k on-die cache, and clock speeds of 1.13 to 1.4 GHz), you get an initial performance boost from the doubling of the cache, but little to no returns from increasing the CPU speed along the 1.13- to 1.4-GHz line. steve |
In article ,
Trevor Hemsley wrote: On Fri, 10 Oct 2003 17:34:03 UTC in comp.os.linux.hardware, (Gregory L. Hansen) wrote: There's a wide range of prices, so I tried to generalize, and I was looking specifically at PIII 600MHz 512 cache. I was thinking especially of a matched pair I saw for something over $100, although they had 256K cache. The fact that the top speed for this board is 600MHz leads me to think that it will only work with the "Katmai" flavour of P-III not with its successor the "coppermine". The Coppermine was the one where they halved the amount of L2 cache on the basis that they made it full speed at the same time. These chips require a lower core voltage than the Katmai ones and some motherboards don't have voltage regulators that are capable of supplying the correct one. So, if it says top speed is 600MHz they probably mean that you're limited to the older, 512KB cache, P-III's. I didn't realize there was such a difference between a PIII 600MHz 512K cache and a PIII 600MHz 256K cache. Are all PIIIs with 512K Katmais, and all PIIIs with 256K coppermines? When I asked about the VRM, I was told the part number 0950-2837 was for any PII/PIII up to 600MHz, and they specifically said it's not for "coppermine". I've asked if the machine would support a faster PIII if a different VRM were installed, but haven't gotten an answer yet, and I'm beginning to wonder if I will. I think the motherboard has the 440BX chipset, if that makes a difference, but I know it also matters which motherboard the chipset is sitting on. And maybe a BIOS upgrade, which HP may or may not have, and which I've never done. The more I learn about this, the more it all gets complicated by little bits of information like what you've just said above. -- "Is that plutonium on your gums?" "Shut up and kiss me!" -- Marge and Homer Simpson |
On Fri, 10 Oct 2003 15:22:34 +0000 (UTC), Gregory L. Hansen wrote:
It looks like the machine I have (an HP Kayak XAS, you may have seen me mention it already) can be upgraded from a PII 400MHz to dual PIII 600MHz. But the PIII's are substantially more expensive than the PII's, around $70 each compared to $10 each. I guess I'm not that excited about a 50% increase in clock rate, by itself. But is there a great advantage just in going from a PII to a PIII with a comparable clock speed? Would I get substantially more computing for the money? For $140 you can get a new case that'll accept standard motherboards and a motherboard'n'cpu on ebay that'll be twice as fast as a pair of P3-600s. |
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