PCI-e Frequency more than 120?

IceVip

Honorable
May 2, 2013
74
0
10,640
My motherboard is Asus P5QL, i've reached the maximum overclock possible for my q9550, which is 3.595mhz, the pc has been like this since 2 years(its 100% 24/7 stable at 55C max, full load).
I've seen alot of people saying that 105+ pci-e will damage the gpu, so its better to lock it at 100, well i tried that today, the pc did not post, i tried 105, then 110, then 115, 120, It still did not post, It was always on auto, but guessing it doesn't post on 120, i mean hell, its even more than that but i don't really have the balls to check the real freq.

Can any1 tell me why is it not possible to change it from auto to 100?
Additional info: GPU: 7870 (1 week old),b4 that i had a(6870, 2 years old)
 
Solution
This is a bit old, but I did some tests on PCIe frequency. I started doing a few more tests on it not too long ago but lost motivation as some other things came up and I haven't got around to finishing the new benchmarks... either way, should help.

http://www.tomshardware.com/forum/260686-29-pcie-frequency-helping

As for why you can't take it off auto? Hard to say. 100 is generally the norm. In the end though, as my results show, it doesn't really make a whole lot of difference.
^ Concur
The Base freq (100 MHz).
PCI Bus MAX is listed at 109 Mhz, but generally Unstable above 105 Mhz.
As henydiah stated: however as it also effects southbridge and Northbridge - IE HDD and Memory.
.. For example on pre SB and IB. the 100 Mhz went to a frequency multiplier before going to CPU/Ram. For example, I set my i5-750 to 400 Mhz bclk. For CPU I then set the Multiplier to 8 for an OC of 3.2 GHz. For Ram I used a 2:1 multiplier to run ram at 1600 (400 x 2 = 800 x 2 = 1600. Raising the 100 -> just 105 would have resulted in a CPU Freq of 3.36 GHz (Cpu could have probably handled this) BUT it also changed Ram from 1680 - More a problem as it is only certified to run UPTO 1600.
.. For the GPU it also is the freq appled to the GPU clock multiplier and the GPU memory Multiplier. Hense affecting their stability.
 

IceVip

Honorable
May 2, 2013
74
0
10,640
I appreciate the info but its nothing close to what i need, sure pci-e freq above 105mhz can cause damage but i don't have 105+ by choice, i have it automated by the motherboard, what can i do to make it go down to 100 mhz without underclocking the cpu?
 
This is a bit old, but I did some tests on PCIe frequency. I started doing a few more tests on it not too long ago but lost motivation as some other things came up and I haven't got around to finishing the new benchmarks... either way, should help.

http://www.tomshardware.com/forum/260686-29-pcie-frequency-helping

As for why you can't take it off auto? Hard to say. 100 is generally the norm. In the end though, as my results show, it doesn't really make a whole lot of difference.
 
Solution

IceVip

Honorable
May 2, 2013
74
0
10,640


I made the FSB go down to 419, then i put the pic-e freq on 100, the pc posted, it wont post if i go 420 fsb, it honestly makes no sens to me, thanks for your reply.