HyperTransport/CPU-NB speed

SMAndy · 27 Nov 2009 at 08:31

Hi Guys,

Well, I'm working on trying to OC my Phenom II 720 BE beyond its current 3.5Ghz. Can't figure out why its not going further. Fails on Prime95 in a matter of minutes if i try it on 3.6 by increasing the multiplier.

Please, check my sig for the cpu-z validation that should show most, if not all.

as an overview, small increase in HT-ref, multiplier for the rest. voltage is currently on 1.425-1.45 (tried either... works on both, so i figured since the temp is low, i could get a more stable clock at the higher voltage)

Temps are idle 21-22°C. At load (prime95, 3 hours) 35-38°C. I think speedfan shows the CPU-NB speed, and if I'm right, its never higher than the mid 40s

How much of a performance loss will i see by lowering my hypertransport or CPU-NB speed to 1.8Ghz as opposed to its current, and stock 2.0Ghz? I'd guess not much, but will i get more total performance out of it by the core speed increase I'd get by doing this?

The only Overclocking I've ever done is what I've done here already. Never done anything on the Hypertransport speed or CPU-NB speed.

Thanks in advance.

Martini1991 · 27 Nov 2009 at 09:14

Take the CPU NB, raise it to 2.6GHZ, but raise CPU NB voltage, raise HTT to 2.4GHZ
On my Phenom II (Sig needs updating), I'm 100% stable under 62C at maximum on intelburn test at 1.5V CPU, 3.7GHZ, 2.6GHZ HTT, 2.8GHZ NB.

SMAndy · 27 Nov 2009 at 09:34

Wow. Nice speeds! The 940 is the quad core equivalent of the 720, right?

What have you got your CPU-NB voltage at? and what cooler are you using? I'd guess a TRUE rev.c would be able to handle it.

I'd love to get my system running that fast. Any idea what safe temps for the CPU-NB are as well? I know its safe to go to about 60° for the CPU itself, but with the CPU-NB being part of that, is it the same?

Thanks for the suggestions

Martini1991 · 27 Nov 2009 at 09:42

I think I'm using 1.475v on the CPU NB, it's probably overkill.
The 940 is 3GHZ quad black edition.
I'm running a multiplier of 18.5.
My C3 arrives in a few hours, I hope to break 4.2GHZ.
I'm using a Black T.R.U.E with two Antec 12 Cm 79CFM fans.
Max temp of the Phenom II is around 62C, but at stress testing, it's safe to go slightly higher, as it'll never be pushed that hard unless you're doing more than gaming.

SMAndy · 27 Nov 2009 at 18:05

Thanks. Got it up to 2266Mhz on the CPU-NB and the HyperTransport already

It failed a prime after 38 minutes with it on the next step up though... I'll leave it like this for now.