Q9550 question - voltage drop under load

[Jeff7181]

I have a Gigabyte EP35-DS3L motherboard (F4 BIOS) and I've had an E8400 in it for the past 4 years. I just recently bought a used Q9550 from a fellow AT Forum member. CPU works great... I say great because it has been running fine while undervolted quite a bit. VID for this CPU (C1 revision) is 1.2500. Right now with the CPU basically idle, Core Voltage is displayed in CPU-Z as 1.232V. When I start up 4 Prime95 threads it drops to 1.200. This is with the voltage set in the BIOS to over 1.26

My question is, is it more likely that this is a motherboard problem, a power supply problem, or a CPU problem?

 

[Jeff7181]

Forgot to mention... the other problem I'm having is that the PC will no longer resume from sleep. It powers on, but monitor gets no signal, lights on keyboard/mouse don't come on, but the power light on the PC is on. I figure that could either be hardware related to this voltage issue I'm seeing, or a HAL issue. Thoughts on that?

 

[2is]

None of the above. That's vdroop in action and the Gigabyte boards of that era have a lot of it. Not really a defect, just a characteristic. I had a DS3R (slighly better than the L) with a Q6600 and it did the same thing. Don't expect huge overclocks from the L version on a quad core CPU. The R has better power delivery and I could only manage ~3.3GHz prime stable

 

[Jeff7181]

I'm not that concerned about overclocking, I just want it to sleep and resume from sleep rather than rebooting or resuming from hibernation. I was thinking the voltage might have been causing instability while resuming from sleep.

 

[Jeff7181]

I set the sleep mode in the BIOS from S3 to S1 and it sleeps and resumes just fine. But if I'm going to do that, I may as well just not even put it to sleep.

 

[VirtualLarry]

sleep problems can be as much about the drivers loaded in the OS, as they can be the motherboard. Does it have sleep problems, if you are running bone stock?

 

[Jeff7181]

sleep problems can be as much about the drivers loaded in the OS, as they can be the motherboard. Does it have sleep problems, if you are running bone stock?

Yes, I've had an E8400 in it for 4 years with no issues. Replaced it with this Q9550, not overclocking it at all, and it won't wake up.

 

[VirtualLarry]

Running the newest BIOS version?

 

[Jeff7181]

Running the newest BIOS version?

No, not the latest, but 3 versions newer than the minimum that supports the Q9550,and it worked fine with the E8400 just hours before I swapped them.

 

[2is]

But a Q9550 isn't an e8400. I'd try the bios update.

 

[Jeff7181]

Ok... worth a shot I guess.

 

[Jeff7181]

The BIOS update did the trick. Thanks for not overlooking it or dismissing it like I did and making the suggestion anyway.

 

[wilson0416]

What's a normal max overclock for the Q9550?

 

[wlee15]

My old C1 Q9550 went to 3.6ghz on 1.28V.