For some Easter entertainment I upgraded from cheapy old Core2 system to a Phenom II 965 Black and set to work seeing what overclock I could manage. System is now as follows:
Phenom II 965BE - I believe it's a C3 (125W), that's what CPUZ thinks anyway.
Xigmatek Dark Knight cooler
Asus M4A77D (AMD 770) motherboard
6GB DDR2 (2x4GB Mushkin DDR2-1000, 2x1GB Geil DDR2-800 - the latter I had laying around so threw it in too - all running at 800MHz for now)
XFX Radeon 5850
PSU is a Hiper Type M 630W - in my mind its a sturdy unit from a brand I've used for a long time without issue, but I don't hear much praise for Hiper these days either so I figure they're somewhat unloved.
This is my first time overclocking a Phenom II - most of my recent experience is with Core2Duos, used to overclock AM2 Athlon64 X2's though. . .but my, things have changed a bit. Seems there are far more things to tweak these days. No longer just "FSB" and multiplier, there's now CPU Northbridge and HT link speed to confuse me. . . . and its not just "keep it under 1000MHz" any more.
So far I've been leaving most things on auto and just tweaking the CPU multiplier and VCore to get a feel for things. I tried tinkering with upping the FSB a few points and dropping the multiplier, but it seemed to make things unstable quite quickly, and my ram is refusing to overclock when I up the FSB. . . which is odd. 205MHz FSB and the ram's still sitting at 800MHz - there must be some kind of lock in there I haven't found how to turn off.
Man, this is getting long already. I'll cut to the chase. So far I've got to 200x19 = 3800MHz, but to get this stable I've had to up the VCore to 1.475V. Temperatures are maxing out at 49/50C after extended stressing. This VCore seems a bit high when I see some folks talking about 3.8GHz at stock volts.
I think the issue is Vdroopage. At first I thought I was stable at 1.45V - it ran for 8hours Prime95 small FFT without issue. It crashed out of Prime95 in-place-FFT though (maximum CPU power draw) within a couple of minutes. During in-place-FFT VCore was drooping down to below 1.4 volts, and occasionally dipping below 1.3v.
A bios update seemed to smooth out the VCore a bit . . . I plotted graphs but I don't have them to hand at the moment. The droop was only occasionally dropping below 1.4v now, but dropping VCore to 1.46V in the bios caused a bluescreen during prime, so it obviously wasn't much improved. Monitored the 12V rail during prime too, and it's stuck rigidly at 12.6V - yes, this PSU is renowned for keeping a high-but-just-within-spec 12V rail, so I don't think the PSU is necessarily the problem.
So here I am. . . I'd love to go faster and/or cooler, but not sure where to go from here. Don't know if the PSU or motherboard (more likely?) is the cause of the Vdroop, and how much is normal with one of these chips. What would you more experienced folks look at next?
Phenom II 965BE - I believe it's a C3 (125W), that's what CPUZ thinks anyway.
Xigmatek Dark Knight cooler
Asus M4A77D (AMD 770) motherboard
6GB DDR2 (2x4GB Mushkin DDR2-1000, 2x1GB Geil DDR2-800 - the latter I had laying around so threw it in too - all running at 800MHz for now)
XFX Radeon 5850
PSU is a Hiper Type M 630W - in my mind its a sturdy unit from a brand I've used for a long time without issue, but I don't hear much praise for Hiper these days either so I figure they're somewhat unloved.
This is my first time overclocking a Phenom II - most of my recent experience is with Core2Duos, used to overclock AM2 Athlon64 X2's though. . .but my, things have changed a bit. Seems there are far more things to tweak these days. No longer just "FSB" and multiplier, there's now CPU Northbridge and HT link speed to confuse me. . . . and its not just "keep it under 1000MHz" any more.
So far I've been leaving most things on auto and just tweaking the CPU multiplier and VCore to get a feel for things. I tried tinkering with upping the FSB a few points and dropping the multiplier, but it seemed to make things unstable quite quickly, and my ram is refusing to overclock when I up the FSB. . . which is odd. 205MHz FSB and the ram's still sitting at 800MHz - there must be some kind of lock in there I haven't found how to turn off.
Man, this is getting long already. I'll cut to the chase. So far I've got to 200x19 = 3800MHz, but to get this stable I've had to up the VCore to 1.475V. Temperatures are maxing out at 49/50C after extended stressing. This VCore seems a bit high when I see some folks talking about 3.8GHz at stock volts.
I think the issue is Vdroopage. At first I thought I was stable at 1.45V - it ran for 8hours Prime95 small FFT without issue. It crashed out of Prime95 in-place-FFT though (maximum CPU power draw) within a couple of minutes. During in-place-FFT VCore was drooping down to below 1.4 volts, and occasionally dipping below 1.3v.
A bios update seemed to smooth out the VCore a bit . . . I plotted graphs but I don't have them to hand at the moment. The droop was only occasionally dropping below 1.4v now, but dropping VCore to 1.46V in the bios caused a bluescreen during prime, so it obviously wasn't much improved. Monitored the 12V rail during prime too, and it's stuck rigidly at 12.6V - yes, this PSU is renowned for keeping a high-but-just-within-spec 12V rail, so I don't think the PSU is necessarily the problem.
So here I am. . . I'd love to go faster and/or cooler, but not sure where to go from here. Don't know if the PSU or motherboard (more likely?) is the cause of the Vdroop, and how much is normal with one of these chips. What would you more experienced folks look at next?