Fault finding a friend's Phenom II 2.7GHz

[Inquisitor M]

Need some advice here!

AMD Phenom 2.7GHz @ stock + GTS 260

System was experiencing severe slowdown when running games, as if the procesing power was dropping through the floor, then recovering, then dropping again.

First thing I did was install coretemp/cpuz/IBT and get a feel for his system. Burn Test was reporting only 3.5GFlops on the first pass (normal stress) and went down from there, barely more than half what I'd expect it to be. Core temps got up to around 77c on full load.

1st anomaly: Core Temp readings were jumping from around 60 to 70+ and then back, at a fairly regular interval. Seems to imply some form of sensor malfunction to me, but I wondered if anyone has seen anything similar.

2nd anomaly: Forced the guy to clean out his heatsink/fan, didn't drop much but it had an effect (needs a better clean with proper tools to hand) on temps, and seems to have lightened the loss of processing power and restored IBT's tests to around 7GFlops (About what I'd expect), which made no sense to me.

3rd anomaly: Clock frequency doesn't drop when idle. Now I don't have any experience with AMD chips yet, but I was under the impression that AMD Cool'n'Quiet basically worked the same as Intel's Speed Step. If this is not the case, could anyone explain how it does work so I can fit it into the investigation?

Only thing I can think of at this stage is that somewhere in my lack of knowledge about Cool/n/Quiet, there is some reason why it is kicking in and hamstringing his PC's performance, possibly due to dodgy heat sensors. Need some ideas and opinions please!

Scott

 

[HazardO]

Does the jump in Core temps correlate with increased/decreased CPU frequency?
It could be that the CPU is being throttled when it thinks it's too hot, cooling down, and then going back up to full speed (until it thinks it's too hot again). If that was the case, an uprated cooler might help.

 

[Inquisitor M]

Well, I'm assumong something along those lines, but unlike when I was testing my Core 2 Duo the stats do not change in the core temp display. Hence why I was asking how cool'n'quiet works, because for all I know I /should/ be seeing the clock multiplier throttle when idle, which currently it is not. I also don't know what the AMD chip actually does when it throttles at thermal cap, so it's hard to take it into account.

Specifically, at no point do I see the clock frequencies change, at this stage I am really just taking a stab in the dark based on what evidence I can see, which is that it's bevaving like a much lower clocked CPU when it's going wrong.