What is my bottleneck?

sumthins fishy here

your telling me

both are using onboard graphics because these rigs are built for raw CPU power, so only the ram/cpu matters

http://products.amd.com/en-us/Desk [...] 526&id=534

less cache and speed ... sounds very weird.

I bet some apps in the background are chewing up cpu cycles on the 945 ... or your mobo drivers are not happy.

Try hyjackthis and a driver update / reinstall.

Some thoughts I have. The most obvious difference between the rigs is the chipset. I had thought that the 790 was better then the 8100, but perhaps the 8100 has a better subsystem. The only other idea I have is what did AMD change between the 8xx and 9xx series? The 8xx has 4MBs of L3 cache, while the 9xx has 6. Digging deep in my memory, I recall an article about AMD increasing the latency of the L3 cache to support more memory. If true, the difference in chipset and changes in L3 speed is probably the 10% difference your seeing.

Reset 945 to stock clocks and try then, could be some bug @ overclocked speed or mismatching CPU/HT/RAM speeds.

Looks like its the chipset then. The 8100 constantly has turned in the better performance. I have no idea why this would be.

It could also be that the ECS > Biostar. Perhaps the Biostar has "noisy" ram traces or something like that. Does the Biostar speed up if you set the clocks back to stock? Can you test with some other program to see if its something related only to 3D studio?

Sorry, I didn't mean to imply that the 8100 is a better overclocker. It does seem to be the better chipset based off of what your giving us.

If the 790 has all those adjustments, its possible that you need to adjust some of them so the 790 is running at its full potential. If the 790 needs a bump in vcore and a change in dram latency, it might provide better numbers. Just because the OC is stable doesn't mean there isn't room for improvement. Also, if its only 3Dmax that shows this, there might be something else entirely going on.

As I tried to imply earlier, it might be because its a biostar, not because of the 790 chipset. If the biostar used cheap materials, or a 4 layer PCB and not a 6 layer, then you might have some signal problems at higher HTT speeds. You didn't list your RAM speeds, so I don't know if this is the problem. (with the memory controller on the CPU, you might be having the classic sync/unsync'd issue as well.) If the CPU has to issue the memory request more then once, or if one system is running sync'd while the other isn't, they could cause one system to finish first. There's a lot of variables at work here, including whether a better 790 board would have the same problem. I wonder if anyone else can look into this, you have me curious if the 790 isn't as good as we all think it is.