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I see where a lot of guys are running it between 118-125 instead of the default 100 to help there 7900's... I was wondering if it is only helpful for SLI setups, or do single card systems seem to benefit as well? Also, would increasing the PCI-E frequency have any effect on other PCI-E cards (such as a PowerColor Theater 550 tuner)?
-Thanks
It's also very helpfull on single cards, yesterday we tested it on a 7900GTX and it workes fine. Without raising up we had 770Mhz on the core and when we lifted up to 120 we could bensh at 840 MHz :clap:
Does anyone know why it helps improve the overclock ? Normally you have to lessen off things to get them to go higher, not turn them up :confused:
Does the voltage supplied to the card through the Pcie slot increase slightly with higher Mhz bus ?
Regards
Andy
does taht also help von 7800´s? do i need 2 run them colder or can this b done on air? i ran mine @ 105 4 a long time, on air.
greetz
Anyone tried this with any ATI cards?
Can it damage any hardware when upping it a lot?
I've read about upping the PCIe bus results in corrupt SATA disks...
I had the bus up to 118Mhz with my 7800GTX which gained me nothing.. 2 weeks later my Maxtor 250GB SATA disk died.. coincidence or a result of upping the bus...
Not sure about overclock but the thing is that bandwidth is increased, thus better results. Same for PCI slot if you rise it from 33.
Yes, SATA gets corrupt if PCI-E is too high and have PCI-E sata controller, but it should be fine up to 120. If you want more, use ATA disks :)
zakelwe, I don't think voltage goes up, it's DC. With AC voltage you would have that effect when upping the frquentie, but not with DC. Overclocking the PCI-E bus will make it possible to send more data to and from the vga card, thus u will have more bandwith. But still, it shouldn't affect the vga core thought.Quote:
Originally Posted by zakelwe
I actualled envisioned the voltage being stepped up by the BIOS if the frequency was increased rather than the frequency causing the voltage to rise, but you are probably right and it does not increase.Quote:
Originally Posted by wittekakker
Regards
Andy
higher pcie=better performance? i still donno yet :P any1 can find out?
greeetz
you can overclock much higher, but the performance is the sameQuote:
Originally Posted by nike
I actually tried it yesterday...my 7900gtx does 694/882 on normal stock air at 100mhz artifact free through ATItool.....bumbed it to 125mhz and it improved to 712/913 before the artifacts started to show their ugly head...this is with a single card mind you as my other one from RMA has not got here yet......stock cooling fan and volts
ah i think i understand it now, so i need 2 up it a lot eh? ;D
I also tried it at 115mhz just to see and the gains were marginable. Seems the more you take it the higher it went. I never tried to see how it scaled though....125mhz was also the highest that I took it....I dont leave it there also, just when I bench
same effect with ati cards?
i thought ati couldnt handle high pci-e freqs well?
Aren't you confusing it with AGP?Quote:
Originally Posted by GoThr3k
Both my X1800XT and GTO gain more points from increasing the PCI-E frequency to 110.
no :p:Quote:
Originally Posted by wittekakker
it might be that it was the previous generation of ATI tough not sure
I have ran my pcie freq at 105 since day 1 of getting my board and card and have never had an issue. 105 is a far cry from 125 though.
When I upped the PCI-E to 110 from 100 it got unstable right away. I have an x800xl w/ vf900. So I think that would be true.Quote:
Originally Posted by GoThr3k
ohwell. I was about to go try it.Quote:
Originally Posted by @_dud
What? Since when do you decrease things to get higher OC? You want to overclock your CPU, you up the HTT and increase the voltage. What do you ever decrease to overclock higher?Quote:
Originally Posted by zakelwe
he means timings
Timings are a latency, its the delay between clock cycles, obviously less delay = faster. That is completely seperate from PCI-E frequency which is a bus speed, higher speed = faster.Quote:
Originally Posted by STEvil
upping the PCIe frequency depends on your MB. Some MBs up the PCIe automatically while others require manual adjustment. The one thing I do know is that the PCIe is connected to the SATA on most MBs. If you want to up the PCIe its best to not have a SATA drive enabled. Again, this depends on the MB.
Isn't sata normally connected to PCI frequency? (= 33.33MHz)
So PCI-E frequency has nothing to do with this
If you want to overclock your CPU you decrease your HTT so it is not an issue so you can see what the cpu limit is. If you use x5 multiplier on an nforce3 board and then start using 250x10 then the HTT will cause the problem and you will never max out your cpu or memory.Quote:
Originally Posted by HiJon89
If you want to overclock your FX nvidia video card and avoid throttling you ease off the RAM so the gpu can be maxed out ( or conversely with a bandwidth starved card such as 6600 you ease off the gpu and go for the memory)
Do you get my drift ?
With overclocking the gpu on Pcie you would not want normally the Pcie bus being overclocked so as to limit you. But the reverse is the case this time.
Regards
Andy
If you guys hit a wall where you stop seeing gains or functionality around 122-124mhz pci-x in SLI, it because there is a limitation on the nf4 chipset. The cards just don't work over 930-940 core in SLI. Never tried on a dual 16x nf4 board, but I suspect there may be less problems with the increased lanes. With single card, you should be able to run pci-x around 134-136mhz without issues on nf4.
Of course on am2 the pci-x issues are completely gone but you can still work around it on nf4 when benching from air to SS cooling. NVIDIA directly addressed this issue with am2 :)
Million dollar question is if this issue will exist on conroe/merom setups when trying to push the cards on ln2 on an "officially" unsupported dual vga mobo.
Whats the mhz sweetspot with 7900gtx in sli
on the Foxconn C51XEM2AA ? :)
I'snt PCIe frequency used for clock generation on the GPU? Perhaps the higher or lower frequency is easier for the GPU to lock on to?
I have no idea if this is true, just a guess :)
Tom
Linkboost locks it down at 125mhz and your good for well over 900 before you have to start messing with anything.Quote:
Originally Posted by Dynasty
1050mhz@ -100c SLI is my new sweet spot. That speed likes around 139mhz.
k|ngp|n, do you use SATA drives and if so have you noticed any corruption at frequencies that high?
i dont think he has sata drives??
i dont know
saw to gain for me. but my asus mobo has PEG link set to auto so it may auto bump the pci-E speed up?
increasing pci freq--->increasing bandwidth i don't understand how this can make performance go up if pci ex its not used completely by gfx cards!improvements must be somewhere else.. waht do u think?
You increase the speed of a bus, thus the data gets elsewhere faster.