WilliamP Posted October 10, 2009 Posted October 10, 2009 I have a GIGABYTE GA-EP45-UD3P mobo and I am running an E8500 @3.8 and everything is fine. I have noticed that it is recommended that the PCI Express Frequency should never be left on Auto. Is this correct? If so why? Share this post Link to post Share on other sites More sharing options...
N.E.A Posted October 10, 2009 Posted October 10, 2009 just to be safe and not to harm the slot or the card , i think Share this post Link to post Share on other sites More sharing options...
RHKCommander959 Posted October 10, 2009 Posted October 10, 2009 I have a GIGABYTE GA-EP45-UD3P mobo and I am running an E8500 @3.8 and everything is fine. I have noticed that it is recommended that the PCI Express Frequency should never be left on Auto. Is this correct? If so why? I am not familiar with that board but in the olden days when you would change FSB, unless you specified the speed for the PCIE then it would rise with it. and it doesnt need to be oced so set it to 100. Just like when you change FSB, the memory speed increases. Share this post Link to post Share on other sites More sharing options...
WilliamP Posted October 10, 2009 Posted October 10, 2009 Thank you. It is now at 100. Share this post Link to post Share on other sites More sharing options...
WilliamP Posted October 10, 2009 Posted October 10, 2009 (edited) Thank you. It is now at 100. Edited October 10, 2009 by WilliamP Share this post Link to post Share on other sites More sharing options...
paulktreg Posted October 10, 2009 Posted October 10, 2009 I have always thought and read that leaving it at 100MHz is the way to go and increasing it can cause instability? It's odd though that in can be increased in bios but I believe it is changed to benefit some graphics cards? Leaving it on auto, as far as I can see, would be the way to leave it, if it needs changing for a particular graphics card then it will take place "automatically"? It is never advisable to change it as far as I am aware and is best left alone, even when overclocking? You'll notice all the question marks so if anybody knows any different then please post. Cheers Paul Share this post Link to post Share on other sites More sharing options...
RHKCommander959 Posted October 10, 2009 Posted October 10, 2009 I have always thought and read that leaving it at 100MHz is the way to go and increasing it can cause instability? It's odd though that in can be increased in bios but I believe it is changed to benefit some graphics cards? Leaving it on auto, as far as I can see, would be the way to leave it, if it needs changing for a particular graphics card then it will take place "automatically"? It is never advisable to change it as far as I am aware and is best left alone, even when overclocking? You'll notice all the question marks so if anybody knows any different then please post. Cheers Paul leaving/setting it to 100 is the way to go, increasing can cause instability or worse. It can have small benefits but are they worth the risk to your hardware... Some BIOS leave or hide the feature, or give suggestions on it. Increasing it can give a performance boost but it can also harm other things. I am not sure if PCI clocks increase with the PCI Express clock rate as they did with AGP and PCI clocks. PCI usually runs at 33MHz , AGP at 66MHz, and PCIE is 100MHz (all multiples of 33) so increasing it may change the PCI speeds. I am a bit grainy though so I do not know if they reference each other as they did in AGP days but I wouldn't be suprised if they did. Share this post Link to post Share on other sites More sharing options...
paulktreg Posted October 10, 2009 Posted October 10, 2009 Whether at Auto or 100MHz I think the best thing to do is leave well alone? Cheers Paul Share this post Link to post Share on other sites More sharing options...
Zertz Posted October 10, 2009 Posted October 10, 2009 Whether at Auto or 100MHz I think the best thing to do is leave well alone? I set it at 100 MHz just to make sure it's locked Share this post Link to post Share on other sites More sharing options...
RHKCommander959 Posted October 10, 2009 Posted October 10, 2009 I set it at 100 MHz just to make sure it's locked exactly. Auto can (depending on mobo) automatically change it with fsb. Share this post Link to post Share on other sites More sharing options...
AIinc Posted October 11, 2009 Posted October 11, 2009 With the newer motherboards the FSB is not connected to the PCI-E frequency. You can take the FSB as high as you want to, and the PCI-E frequency will stay at 100MHz, which is the default setting. Share this post Link to post Share on other sites More sharing options...
Hedghawg71 Posted October 11, 2009 Posted October 11, 2009 (edited) I know back in the day I had a couple of XFX 7900GTX's that ran solid and stable at 125mhz on both pci-express slots on an ASUS P5n32SLi with no issues for almost a year. BUT my next card after that, The 3870X2 at 102mhz on the same motherboard crashed like a drunk teenager in a sports car. Here not too long ago I burned up a XFX 4850 pushing the PCI Express above 115mhz on a 790fx motherboard. It only recognizes 512 of it's 1gb memory and runs at 4x flat out in a 16x slot. I'd say lock it in at 100mhz and leave it alone too. It's way too risky to mess with. The unpredictability factor is high. Edited October 11, 2009 by Hedghawg71 Share this post Link to post Share on other sites More sharing options...
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