PCIe Speed Test v0.1 CPU-GPU/GPU-CPU bandwidth test

[Mechromancer]

Tri Fire. 3x3870 2x3870 gave the same


Single 3870


Tri Fire. 3x3870 bumped up PCIE from 100Mhz to 175Mhz. 1.250v on the PCIE. Ran PCIE at 200Mhz did not improve anything from 175Mhz & i don't feel like pushing to 250Mhz.


VC1 Traffic, Isochronous Flow Control Mode, UnitID Clumping 2/3&B/C, 2x LCLK Mode all on.

Are all of those test with the Isochronous Flow Control options enabled?

hmm. tried leaving it to run a while. definate freezing at random intervals. i tried leaving it a few minutes - no luck. i may leave it to churn while i go to sleep. but it stops after a few seconds so i dont hold out much hope for a full run.

it seemed to run better when invoked from cmd directly and not from explorer. also seems to get further with ccc closed.

is anyone running this tool successfully under an x64 system?

my cpu->gpu is about 5gb/s ----- but my gpu->cpu is only geting to about 1.0gb/s

I only run x64 baby! x64 performance is the only performance that matters LOL.

I noticed that stability of the pcie can actually be determined with everest memory speeds. My system hits hits around 9975-10010 in the memory read test when everything is stable at the speeds. It turns out that with pcie at 140mhz at the ht link up at 3072 its not stable with 1.2v on the ht. I knew that because the memory reads were in the 9600s and 9700s meaning something wasn't right. With the voltage bumped up to 1.28v it works fine now and memory reads are back where they should be.

The ht link needing more voltage goes back to the other thread about when I asked why not have the ht link higher since it should bring higher performance. I'm guessing mine didn't need voltage till a while later because the cpu is on phase, but air systems need voltage sooner.

This reminds me of an interesting point I learned about HyperTransport. HT uses LVDS, Low Voltage Differential Signaling (READ HERE) to signal at high speeds, while minimizing signal noise. Because of how HT works electronically, I think there may be a bigger relationship between voltage and frequency than just what voltage you need to make it work. The wrong voltage may impair the actual communication and degrade performance at certain frequencies.

With that being said, the spec says HT is supposed to work all the way up to 2600Mhz at 1.2v so . Mine cannot!