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PCIe Frequency: Safe to overclock?

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December 8, 2007 9:06:10 PM

I read around that overclocking the PCIe to 120mhz brings more overclocking potential to vidcards, thus improving the frames. I also read that overclocking it too high will cause data corruption for SATA drives.

Is it safe to overclock the PCIe frequency? Will I be able to overclock my video card much more than 680/1000? MSI site states anything above 120mhz isn't recommended...
December 9, 2007 5:59:29 AM

Evilonigiri said:
I read around that overclocking the PCIe to 120mhz brings more overclocking potential to vidcards, thus improving the frames. I also read that overclocking it too high will cause data corruption for SATA drives.

Is it safe to overclock the PCIe frequency? Will I be able to overclock my video card much more than 680/1000? MSI site states anything above 120mhz isn't recommended...


I would lock the PCIe frequency to 100mhz. Anything higher can cost instabilities, and I dont believe it would help performance on stock levels or help to achieve higher OC's. I could be wrong, but from experience and what I have read it seems to me that locking it at 100mhz is in most cases going to be your optimal setting. Hope this helps.

Best,

3Ball
December 9, 2007 4:26:16 PM

Thanks for the reply. I know going to high will cause instabilities, but I believe it does increase the frame rates. I just tried it at 120mhz and instead of the usual ~12800 for 3dmark 06, I got a score closer to ~12900. But if it does cause instabilities, probably it's not worth it. However I also read somewhere that increasing it can improve stability.

Now I'm confused :( 
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December 9, 2007 4:30:17 PM

I would run 3Dmark 4-5 times and take an average. Mine are always within +/- 3% of each other and that 12900 is within the 3% error rate.
December 9, 2007 4:32:44 PM

Rigto. I did it around 5 times, each with a setting of higher than 100mhz. To me it seems as if the 120mhz is the optimal spot, since I get ~12900 consistently. Before, I get ~12800, 12817 being the highest I have gotten.
December 9, 2007 4:35:00 PM

Evilonigiri said:
Rigto. I did it around 5 times, each with a setting of higher than 100mhz. To me it seems as if the 120mhz is the optimal spot, since I get ~12900 consistently. Before, I get ~12800, 12817 being the highest I have gotten.



What graphics card?
December 9, 2007 4:38:00 PM

In my sig, the 8800GTS 320mb :) 
December 9, 2007 4:42:22 PM

Evilonigiri said:
In my sig, the 8800GTS 320mb :) 



Haha my bad.

Anyways, have you tried OCing it at 100 MHz PCIe and then again at 120 MHz PCIe? I wouldn't mind seeing some results if you feel like being excessive OCD... I mean Benchmarking 3DMark06 10 times at all stock and getting a baseline. 10 times at OC'd with 100 MHz PCIe, 10 times at stock graphics 120 PCIe, and 10 times OC'd with 120 PCIe and comparing the differences in solid OC, 3DMark06, and if you got any improvement in OC ability.
December 9, 2007 4:47:20 PM

Okay why not? Well truthfully 680mhz isn't stable, just purely for benchmarking. At 100mhz, 670mhz isn't stable either. However when I brought it to 120mhz, I could get to 675mhz without the 3dmark crashing every so often.

I'll update the results a little later.
December 9, 2007 4:52:49 PM

Evilonigiri said:
Okay why not? Well truthfully 680mhz isn't stable, just purely for benchmarking. At 100mhz, 670mhz isn't stable either. However when I brought it to 120mhz, I could get to 675mhz without the 3dmark crashing every so often.

I'll update the results a little later.



Thanks man!

If you're like me I always try to do my own benchmarks. I did my own benches of 1333 MHz FSB vs 1600 MHz FSB and 1066 vs 1333 and so on.

I also try to do my own on memory bandwidth and timings. It's pretty telling to see it for yourself rather than rely on what some website says.
December 9, 2007 5:58:27 PM

If you can, and/or have time for it try to through in some actual game benchmarks as well...maybe something like the source stress test or something? Just curious.

Best,

3Ball
December 9, 2007 6:03:20 PM

3Ball said:
If you can, and/or have time for it try to through in some actual game benchmarks as well...maybe something like the source stress test or something? Just curious.

Best,

3Ball



It's a pretty interesting topic. I haven't seen much on this other than people saying lock it to 100 MHz.
December 9, 2007 7:26:09 PM

cnumartyr said:
It's a pretty interesting topic. I haven't seen much on this other than people saying lock it to 100 MHz.


Well in many OC'ing guides such as the one on these forums it is suggested to leave it locked at 100mhz.

http://www.tomshardware.com/forum/240001-29-howto-overc...

So that is one area where I have seen it, but the discussion came up alot more back when the C2D's and X2's were being learned to be OC'd.

Best,

3Ball
December 9, 2007 8:52:07 PM

3Ball said:
If you can, and/or have time for it try to through in some actual game benchmarks as well...maybe something like the source stress test or something? Just curious.

Best,

3Ball

Too bad I don't have CS installed on my pc :( 

Although I think 3dmark is sufficient when it comes to comparing overclocks, I'll run it through COD4 a couple of times. I'm about half done with my testing, and so far there is a slight increase in performance...
December 9, 2007 10:33:25 PM

Okay finally done with the testings :) 

Objective:
To find if increasing the PCIe frequency improves performance

Test bed:
Q6600 @ 3.15ghz
4x1gig ram @ 700mhz
Xfx 8800GTS 320mb XXX
GA-P35C-DS3R

Procedures:
Set PCIe to 100mhz. Set vidcard clock speeds to stock (580/1500/900). Run 3dmark06 5 times. Then overclock to 665/1618/1000 and restart pc. Run 3dmark 5 times. Repeat for 110mhz and 120mhz.

Results(using 3dmark06):
100mhz PCIe:

580/1500/900
Score:11623

665/1618/1000
Score:12746

110mhz PCIe:

580/1500/900
Score:11624

665/1618/1000
Score:12792

120mhz PCIe:

580/1500/900
Score:11636

665/1618/1000
Score:12807

Highest clock speed(core only)*:
100mhz:665mhz, Score-12746
110mhz:N/A
120mhz:675mhz, Score-12853

*Note this is done by COD4. I ran the whole SP COD4 with the overclocked settings. If it crashed, artifacted, or freezed, I lowered the core clock speeds. I did not want to overclock the Shader clock and memory clock any further.

Conclusion:
Setting the PCIe higher than 100mhz does increase performance slightly. If raising the PCIe does not cause instability, it may be worth it. I'm sure I could raise the memory clock higher, but I feel that 1000mhz is a bit high already.

Well that shows it :p  Increasing the PCIe frequency increases performance slightly and improves overclocking. The temps never exceeded 70C.
December 9, 2007 10:43:45 PM

Evilonigiri said:
Okay finally done with the testings :) 

Objective:
To find if increasing the PCIe frequency improves performance

Test bed:
Q6600 @ 3.15ghz
4x1gig ram @ 700mhz
Xfx 8800GTS 320mb XXX
GA-P35C-DS3R

Procedures:
Set PCIe to 100mhz. Set vidcard clock speeds to stock (580/1500/900). Run 3dmark06 5 times. Then overclock to 665/1618/1000 and restart pc. Run 3dmark 5 times. Repeat for 110mhz and 120mhz.

Results(using 3dmark06):
100mhz PCIe:

580/1500/900
Score:11623

665/1618/1000
Score:12746

110mhz PCIe:

580/1500/900
Score:11624

665/1618/1000
Score:12792

120mhz PCIe:

580/1500/900
Score:11636

665/1618/1000
Score:12807

Highest clock speed(core only)*:
100mhz:665mhz, Score-12746
110mhz:N/A
120mhz:675mhz, Score-12853

*Note this is done by COD4. I ran the whole SP COD4 with the overclocked settings. If it crashed, artifacted, or freezed, I lowered the core clock speeds. I did not want to overclock the Shader clock and memory clock any further.

Conclusion:
Setting the PCIe higher than 100mhz does increase performance slightly. If raising the PCIe does not cause instability, it may be worth it. I'm sure I could raise the memory clock higher, but I feel that 1000mhz is a bit high already.

Well that shows it :p  Increasing the PCIe frequency increases performance slightly and improves overclocking. The temps never exceeded 70C.


Interesting to say the least.

Best,

3Ball
February 7, 2009 1:50:34 PM

pcie frequency when set to auto it will sync with fsb

c2d e6400 asus p5ld2
auto setting
8*266 =2.1ghz > pcie=100mhz
8*350 =2.8ghz > pcie=131mhz

I burned 2 vidcards on 131mhz

evga 7600gt all condensators exploded 1 by 1 (1 per month)
i was lucky i was able to switch them with better japan made

asus ENGTX280 after a month it started artifacting not oced ever
i was lucky guys on RMA didnt know what was teh problem so they sent new card

i am locked at 100 now
but on 8*350 =2.8ghz the lowest setting i was able to get for pc to boot up was pcie117mhz stable

i hear alot that ppl suggest 112 max but i want those 117 and im not sure about it
anyone using above 120 on gtx280 or maybe any other card and doesnt have problems for 3 months?


sata is on pci not pcie and it should be locked to 33.3 i think
June 4, 2009 11:52:29 PM

I increased pci-e frequency from 100 to 115 MHz
in 3Dmark vantage i got a 0.52% increase in the GPU score, 1.07% increase in CPU score and a 0.6% increase in the 3dmark score. The performance gains are not great, but it does give you a few extra frames.
and its stable; ill check 120 MHz another day.

September 5, 2009 6:43:29 PM

I increased my frequency from 100 to 108 and my framerates in Crysis were a lot more consistent...and I mean A LOT more consistent! Sometimes, I'd have 40 FPS for a few seconds then it'd jump down to 28FPS. Now it seems to gradually lower down to 28FPS instead of a sudden decrease
Anonymous
a b V Motherboard
a b K Overclocking
a b U Graphics card
September 17, 2009 9:34:27 PM

my mobo GA-P31-DS3L

wont let me oc my E8400 TO 3.6GHz if PCIE not 118MHz, just resarts bios stats instead :s

glad to know there was some1 doing tests.
October 4, 2009 7:57:15 AM

I got used to rise pci-e instead of using Rivatuner to improve FPS and fluidity in tough game like Crysis Warhead. I have also risen SPP<->MCP freq accordingly.
I have not got problems, I use my rig only for gaming with a Tri Sli Gtx 285, not very concerned about data corruption if the game runs smoother.
On Crysis W. I set to 118 118 118 204
Bye m.o.t.p.
a b K Overclocking
a b U Graphics card
October 4, 2009 8:23:49 AM

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