Overclocking an X2

[Insidious]

So out of the box (A64 X2) 3800+, I fire up MSIs (very crappy) core cell program and check out the temps.. it was running 62C :shocked:

Well, I figured it was a stock HSF after all, and I might have mis-applied the thermal grease (although I have been doing this for a while now)

I continued on my merry way.. I got up to a very UNimpressive 2.16GHz and decided to experiment with various bus ratios a little bit. I bought this snazzy PC3200 CAS:2-2-2-8 RAM and figured, well if I back off those (stock) timings a little, I can rev. up the memory speed and see if that gets me any higher. (CPU was so hot I figured I'd leave it alone and OC the RAM a bit)

I check the temperatures and find a cozy 56C :shocked: WTF... my core volts were still the same (1.4+8.3%).....

Could it be?.... the answer was a resounding YES. I went back and forth a couple times to convince myself...... RUNNING MY RAM AT CAS2 (vs. CAS2.5) raised my Tcore 6-7 degrees! It was the memory controllers frying the innerds of my X2 :shocked:

Long story short... I left my timings at CAS: 2.5-3-3-9 and now have:

CPU = 2500MHz (x10)
HT = 1000MHz (x4
FSB = 250MHz
RAM = 208MHz (x0.83)
Vcore = 1.4V+8.3%
Tcore = 57 (while crunching 2 Rosetta WUs)

Moral: CPU speed is King anyway with X2 O/C's... so run that RAM at CAS 2.5 and run that puppy up past the $630.00 X2 you thought you wanted.

:beer:

-Sid

 

[mikester]

Very interesting. I also noticed a difference in my CPU overclock due to the memory. I initially had my X2 3800+ running at 2.7 GHz with 1 512MB stick of Patriot DDR600. When I tightened up the timings (in particular, setting 1T command rate) my stable overclock dropped to 2.65 GHz. Then when I added the second stick of memory, I had to back off to 2.6 GHz to get it overnight Prime stable.

I attributed this to more stress on the memory controller, but I never thought about the heat aspect since heat hasn't been a problem for me. I'm running at 1.55v and load temps are 49C. I think my cooling could handle a little more juice, but I just don't know if it's safe longterm to pump 1.6v+ through a Manchester core.

 

[Markfw]

I don't know what the deal is with your temps though. Both my X2 3800's are at 1.475vcore, 2550 speed, and run ~51c with XP90's. At 1.4 vcore those temps sound high. The only OC I have tat is at 1.4 vcore, is my Opteron 170, and it runs the same speed, but at 37c ! (all temps both cores 24/7 100% load)

 

[Insidious]

Originally posted by: Markfw900
I don't know what the deal is with your temps though. Both my X2 3800's are at 1.475vcore, 2550 speed, and run ~51c with XP90's.

Edited because my answer sounded snotty... Sorry to you Mark... didn't mean it
I think the difference in our heat sinks xp-90 as opposed to stock plus the difference in our Vcore (I am at 1.52V) explains the differences we are seeing.

-Sid