FSB experiences a decline in performance after prolonged use.
FSB experiences a decline in performance after prolonged use.
So I've encountered some strange behavior with an old computer of mine. After being used for a while, wether web browsing or gaming, it starts to become really slow. After checking HWiNFO64 it seems that the FSB speed is dropping from 267 MHz to 127 MHz, causing the CPU to become really slow, and it never recovers from this state unless the computer is restarted. CPU temps don't seem to be the issue, as they only reach about 50-60 degrees C, however these is one temp reading labeled "Auxiliary" that reaches 80 C. In fact, through testing and monitoring it looks like this behavior starts the moment it reaches 80, but even when temperatures fall below this, this slow down or throttling does not go away. Something else interesting is that HWiNFO64 seems to be the only application that catches this behavior, other similar software does not show a lowered FSB speed, but benchmarking will show diminished performance. What could be the cause of this? I've personally never seen this behavior before on any other computer.
Specifications are as follows:
MB: MSI MS-7528
CPU: Intel Core 2 Quad Q6600 (G0)
RAM: 4GB DDR2 at 400 MHz (effective 800)
GPU: NVIDIA GeForce 8800 GTX
A pretty old system, I know, but I wanna keep it around.
Check if the thermal pad or paste under the motherboard heatsinks is in good condition. I don't remember if that setup had power-saving features for FSB control. I haven't owned a Core 2 Quad before, though I did overclock one once.
There are two heatsinks on the MB, one marked NB and another SB, likely representing the northbridge and southbridge. Both appear to overheat significantly, with the northbridge nearly reaching a burning temperature. This isn't the original motherboard for this setup, but a recently purchased replacement for the failed one. Documentation from MSI suggests the CPU should work here, though I'm concerned about whether its power consumption is too high for this board. I also have a Core 2 Duo E7200, which doesn't show the same issue.
Possible. Northbridge and Southbridge are involved; Northbridge handles memory control while the other is the modern PCH with I/O functions. If the heatsinks remain warm, it suggests good thermal contact is still present. Reapplying paste might help. Consider directing a fan at the hotspots to check if performance improves. If so, it indicates the board may not be compatible with the CPU.
I've conducted additional testing, and with a Core 2 Duo I had the auxiliary temperatures hovering around 45 C regardless of the workload. Notably, the CPU temperatures aren't significantly lower, but this FSB throttling problem disappears entirely. It seems the motherboard is technically compatible, though it isn't built for high TDP CPUs like this one (95W versus 65W on the Duo). I think I'll search for another LGA 775 board that fits this CPU.
It seems to be mainly an issue with HWiNFO64, as G31 lacks the capability to adjust the FSB dynamically. The chip's multiplier is fixed at 6x or 1.6GHz due to overheating prevention. Unlike desktop CPUs, Core 2 models didn't offer Turbo, instead using a de-Turbo setting. The multiplier would revert to 6x and remain unchanged until the system restarts. I don’t see a matching BIOS option in your MSI manual.
Another factor is that the G31 can’t address more than 4GB, preventing full RAM utilization even in a 64-bit OS. This results in at least 0.75GB being marked as reserved, making it unusable. The last time I tried a GTX8800 in one, I got only 2.75GB usable in Windows 10 due to driver conflicts.
Today it’s probably not worth the investment, since similar functionality is now available and you’re unlikely to use the system daily. You might want to focus on better cooling or consider a different board. Or simply evaluate whether a quad-core at 1.6GHz would outperform a dual-core at full speed.