Results of "Lapping" a Q6600 for better thermal pe

[Ross Boyd]

Hi,

Maybe a little bit off-topic - however its all about keeping an over-clocked Quad core cool while running tournaments.

I have a Q6600 with G0 stepping on a Gigabyte P35-DS3P Mobo.
Ram is 2 x 1Gb Corsair CM2X1024-6400C4.
Cooling is Thermaltake "Silent Water" which is a nice little budget water cooler.
PSU is only a 400W HEC.

Anyway, the Q6600 is one of the easiest CPU to over-clock. So, I upped the clock speed from 2.4Ghz to 3Ghz. ie. changed FSB from 266Mhz to 333Mhz.

The hottest core was hitting 70C which concerned me a little That's waaay too hot for running long tournaments.

After lowering the VCore voltage from 1.3V to 1.25V the temp came down to 65 C. But still much too hot for my liking.

I read an article on "lapping" the CPU casing and cooling block. Lapping involves (very carefully) sanding the two surfaces till they are absolutely flat and close to a mirror finish (using progressively finer wet-n-dry sandpaper.) You can start with 400 Grit and finish with 2000 Grit.

Its claimed this procedure can reduce temperatures by up to 10 or 12 C.

Here's one guy's description of his attempt with graphs/pictures....

http://forums.pcper.com/showthread.php?t=441410


So, I gave it a try.
BTW: This procedure TOTALLY VOIDS your CPU WARRANTY.

After "lapping" the hottest core now plateaux's at 54 C under full load!
That's 11 C cooler!!

So, the experiment was very fruitful and only cost me $5 for the sandpaper (and loss of CPU warranty).

Also, I highly recommend using free OCCT software as an excellent stress tester which seems to be more reliable than Prime 95 for detecting CPU and RAM instability. It also produces nice temperature charts for each Core so you can document your results.

Here's Core 1 before and after:
Note the first test ran for over 3 hours but the second test I stopped after 30 minutes....

Before:


After:





Happy lapping and happy Quad tournaments,

Ross

[Guetti]

Hi,

The hottest core was hitting 70C which concerned me a little That's waaay too hot for running long tournaments.

Ross

Hm, I though it's normal for these Intel CPU to run up to 90-100°C without problems. I read this somewhere, I don't have one. Maybe somebody can confirm?

- Andy

[Ross Boyd]

Hi,

The hottest core was hitting 70C which concerned me a little That's waaay too hot for running long tournaments.

Ross

Hm, I though it's normal for these Intel CPU to run up to 90-100°C without problems. I read this somewhere, I don't have one. Maybe somebody can confirm?

- Andy

See Intel's specsheet below. They're rated 71°C.

Also, in 1995 Intel published a fact sheet (I can't source it) which said every additional 10°C halves the avg lifetime of the CPU. Not sure if that applies to a Core Duo but it seems a good rule of thumb.

http://processorfinder.intel.com/detail ... Spec=SLACR

[Guetti]

Ok , forget it, I confused it with the mobile Core2 Duo variants:

http://processorfinder.intel.com/detail ... Spec=SLAF7

[Ross Boyd]

Ok , forget it, I confused it with the mobile Core2 Duo variants:

http://processorfinder.intel.com/detail ... Spec=SLAF7

No worries Andreas.

But Wow! That's an incredible thermal tolerance in those Mobile Core2Duos!!

100 C.

I had no idea they could cop such abuse!

Ross

[Marc Lacrosse]

Hi,

The hottest core was hitting 70C which concerned me a little That's waaay too hot for running long tournaments.

Ross

Hm, I though it's normal for these Intel CPU to run up to 90-100°C without problems. I read this somewhere, I don't have one. Maybe somebody can confirm?

- Andy

I have a watercooled Q6600 overclocked at 3650 Mhz.
At full load for long periods (overnight analysis) temperature often reaches 70°C on some cores.
So far nothing negative happened after more than three months at this regimen .

Marc

[Ross Boyd]

I have a watercooled Q6600 overclocked at 3650 Mhz.
At full load for long periods (overnight analysis) temperature often reaches 70°C on some cores.
So far nothing negative happened after more than three months at this regimen .

Marc

Holy SMOKES!!!

But seriously, after reading Andreas post about Mobile Core2Duo's having a 100C thermal limit - maybe Intel are being very conservative in their recommended thermal limit of the Q6600.... (71C). Maybe??

I'm too scared to risk my (now) un-warranteed Q6600 at high temps.

But I really get the impression that the Q6600 can really deliver waaaay beyond its rating. I have seen my memory fail overclock but NEVER the cpu.

Good luck Marc!

Ross

[Spock]

I could be wrong, but I think 71C is not the actual core temps, but the years old measurement of what the temp on the heatspreader, or in some cases they even mean the case temp. I think the Quad Cores are good up to 90-100C internal core temps, but I'd never want to see that myself. Try the older B3 steppings QX6700 with the Intel Stock cooler for example, you won't see anything less than 75C core temp with those under full load. And there is a 3 yr guarantee at those temps. Heck in a hot climate they'd probably be 80C+ and that's still guaranteed.

My QX6700 with a Freezer 7 Pro was 70C core temp on hottest core under load. I ran that at stock 2.66 for a year like that. Given that the Freezer is 5-10C better than the stock Intel cooler.... Then I decided to overclock, and then I got an Ultra 120 Extreme which now runs the cores at 60C at 3.0, huge difference

[Nid Hogge]

My best advice is to dump that TT unit as it really just.. Bad.
You gonna get much better results with decent air cooling.. Here's a few good options:

XIGMATEK HDT-S1283 120mm
http://www.newegg.com/Product/Product.a ... bHDT-S1283

ZEROtherm Nirvana NV120 120mm
http://www.newegg.com/Product/Product.a ... 6835887011

Thermalright Ultra-120 Extreme
http://www.newegg.com/Product/Product.a ... 6835109140

The first 2 are excellent for the price and comes with a fan. The last one is the best but is more expensive and does not include a fan.

You can run safely 24/7 1.4 Vcore with either of those at 3600+ Mhz easily.(Q6600 G0).

Other than that you could invest in a proper WC system .. but that would raise the cost considerably. For about 200-300 MHz overall. not so sure it's worth it.

P.S. Core 2 family stars throttling at 83-85 C .. Have seen it myself. Wouldn't advise running at 70 C + for a long time. Stay in the 50-60 area with good cooling and your fine.

BTW, Core Temp will give you the most accurate temp readings..

http://www.alcpu.com/CoreTemp/