New fan, temperature surprise

First, the hardwa

Abit NF7-S 2.0
Barton 2500+ (OC'd to 3200+ at 1.75V (MBM says 1.71-1.73))
Not mobile, not locked
Thermalright SLK-800A with AS3 and generic 80mm fan
2 256M sticks of Elixir DDR400 (won't run dual channel)
Sapphire Radeon 9800pro (128M)
Maxtor 80G 7200rpm SATA hard disk
Old generic CD-ROM
Antec SL400 (400W 2-fan PSU)
Case ... (the name escapes me, it was the hot case 5 years ago)
mini tower
1 80mm front fan
1 80mm back fan (in addition to PSU fan)

I've assembled this box in bits and pieces, the latest upgrade
being the SATA drive. When I first OC'd the Barton last winter,
the temps were a little high so, not being bothered much by noise,
I put a Thermaltake Smart Case Fan II in the front fan position,
cranked all the way up (4900rpm reported by MBM, 75cmf claimed by
Theramltake). The temps were pretty good according to MBM:
CPU - 38C idle 46C load
MB - 22C idle 27C load

Oh, the back case fan is a generic, two wire but seems to move a
good bit of air and the air coming out always seems cool. The
CPU fan runs at 3500rpm and also seems to move a good bit of air.

Now the fun part. As the weather has warmed, so has the room where
this machine is and the temps have crept up. Load temps started
exceeding 50C CPU and 30C MB. Maybe not really a problem, but I
was bored so I got another Thermaltake, cut a hole in the side
panel and mounted it blowing in, full blast. It is just about
centered on the video card up and down and is lined up with the
CPU front to back. The MB temps dropped back to 21C idle and 24C
load. The surprise?

The CPU temps dropped to 28C idle and 34C load!!!

Nothing else was changed. I thought maybe the NF7 decided that it
didn't like the OC any more and was running the CPU at low speed...
nope, running at 200MHz fsb and 2200MHz internal. I let Prime95 run
6 hours undisturbed and the CPU temp did not go over 34C. I know
the NF7 CPU temp is based on a sensor under the CPU. Maybe I have
created an airflow under there. I looked with a dental mirror...
the CPU socket seems to be tight down to the MB and the CPU seems
to be tight down to the socket. These temps seem too good to be
true. Any ideas?

Bill Sudbrink wrote:
First, the hardwa

Abit NF7-S 2.0
Barton 2500+ (OC'd to 3200+ at 1.75V (MBM says 1.71-1.73))
Not mobile, not locked
Thermalright SLK-800A with AS3 and generic 80mm fan
2 256M sticks of Elixir DDR400 (won't run dual channel)
Sapphire Radeon 9800pro (128M)
Maxtor 80G 7200rpm SATA hard disk
Old generic CD-ROM
Antec SL400 (400W 2-fan PSU)
Case ... (the name escapes me, it was the hot case 5 years ago)
mini tower
1 80mm front fan
1 80mm back fan (in addition to PSU fan)

I've assembled this box in bits and pieces, the latest upgrade
being the SATA drive. When I first OC'd the Barton last winter,
the temps were a little high so, not being bothered much by noise,
I put a Thermaltake Smart Case Fan II in the front fan position,
cranked all the way up (4900rpm reported by MBM, 75cmf claimed by
Theramltake). The temps were pretty good according to MBM:
CPU - 38C idle 46C load
MB - 22C idle 27C load

Oh, the back case fan is a generic, two wire but seems to move a
good bit of air and the air coming out always seems cool. The
CPU fan runs at 3500rpm and also seems to move a good bit of air.

Now the fun part. As the weather has warmed, so has the room where
this machine is and the temps have crept up. Load temps started
exceeding 50C CPU and 30C MB. Maybe not really a problem, but I
was bored so I got another Thermaltake, cut a hole in the side
panel and mounted it blowing in, full blast. It is just about
centered on the video card up and down and is lined up with the
CPU front to back. The MB temps dropped back to 21C idle and 24C
load. The surprise?

The CPU temps dropped to 28C idle and 34C load!!!

Nothing else was changed. I thought maybe the NF7 decided that it
didn't like the OC any more and was running the CPU at low speed...
nope, running at 200MHz fsb and 2200MHz internal. I let Prime95 run
6 hours undisturbed and the CPU temp did not go over 34C. I know
the NF7 CPU temp is based on a sensor under the CPU. Maybe I have
created an airflow under there. I looked with a dental mirror...
the CPU socket seems to be tight down to the MB and the CPU seems
to be tight down to the socket. These temps seem too good to be
true. Any ideas?

That is an exceptional result. I have an XP1800+ running on a 200Mhz FSB @
2.1Ghz using 1.825vcore. I am using the stock AMD HSF but with a case fan
(with a chrome wire finger guard) placed in a hole cut directly above the
CPU, with the incoming air ducted (a cut section of plastic cup hot-glued to
the case fan) directly to the CPU fan. It still runs a little warmer than
I'd like, high 50's (°C) in summer (New Zealand, no AC), under full load all
the time (I'm a SETI cruncher), but before I did that there was no way I'd
get an OC anywhere near that safely using the standard HSF. I'm on a really
tight budget, this method cost about a quarter of what it would have cost to
buy a super-duper aftermarket cooler and gave far better results than a mate
got after spending a fortune on a big hunk of copper and a huge fan. After
all, he's just recirculating warm in-case air, I'm supplying fresh air to my
CPU.

Every time I hear of someone buying an aftermarket whizz-bamg HSF that costs
as much as their CPU and getting a 5°C drop I have a little smile to myself.
I got a 10°C+ drop from my little, cheap, mod.
--
~misfit~

On Fri, 23 Apr 2004 10:52:20 +1200, "~misfit~"
wrote:

Every time I hear of someone buying an aftermarket whizz-bamg HSF that costs
as much as their CPU and getting a 5? drop I have a little smile to myself.

.... you are not alone ... :-)

--
Regards, SPAJKY ®
& visit my site @ http://www.spajky.vze.com
"Tualatin OC-ed / BX-Slot1 / inaudible setup!"
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