E8400 --- 790sli ftw OC Questions..

This is especially for anyone using an eVGA 790 board:

I will try to snag a picture or two of what I am seeing in BIOS later on, but basically I do not have a standard "FSB" option that I can set (e.g. FSB -- 400). I currently have my machine OC'd to 3.6ghz and it is 24/7 stable; however, I would really like to get to 4ghz or even a bit higher--I am just at a bit of a loss when it comes to how I do so.

Currently, to get my machine running at 3.6ghz and my DDR3 to run 1600mhz I have my FSB set to 1600mhz. My option isn't standard 400FSB x9 Multiplier--just tells me to enter a FSB speed. If I set it over 1600 I get all kinds of trouble with my memory speeds. I would like to keep my memory at 1600mhz (since that is what it is set for, and I don't particularly think it would be a great idea to mess with it's clock speed or voltage). If I set my FSB to 1333mhz (stock) my CPU runs at 3.15ghz and my memory also runs at 1333mhz. Basically, I need help figuring out how to set my FSB and Memory independently to achieve 4.0ghz or higher and continue running my memory at 1600mhz, if you have experience with eVGA board please reply!

I know this really isn't enough information to get an accurate answer, so just let me know what else to put up and I will do my best to accommodate. Thanks!


eVGA 709i SLI FTW Digital ( ) (also found this great overview, going to read it today in hopes of getting a better understanding of the board )
E8400 @ 3.6ghz, ~1.265v (I believe--will check the voltage)
Xigmatek Dark Knight cooler
FSB 1600mhz
DDR3 @ 1600mhz 9-9-9-24 2T
Believe my FSB and memory speed are "linked"
15 answers Last reply Best Answer
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  1. 19 responses...this isn't what I was hoping for lol.

    Is my situation screwed up, or what?

    Could I live with 3.6ghz? Absolutely.

    Would I like to get to 4ghz? Absolutely.
  2. Best answer
    Is there an option to unlink the memory? If so, try 1800fsb and set the memory manually. Increase the nForce MCP voltage to the second notch, or the next one if you've already increased it a bit. Dont put the the 'CPU FSB' over 1.2v. Also try turning the vdroop control off.
  3. reduce the mem-fsb ratio so the mem runs at 800mhz, then up the voltage to the cpu and nb, put the fsb to 1778, then if its stable you can raise the mem speed back up.
  4. spixel said:
    Is there an option to unlink the memory? If so, try 1800fsb and set the memory manually. Increase the nForce MCP voltage to the second notch, or the next one if you've already increased it a bit. Dont put the the 'CPU FSB' over 1.2v. Also try turning the vdroop control off.

    Ok, will try this response out first--and yes, I have unlinked the memory, just haven't changed any settings yet (wanted get some input first). Couple questions: why turn off the vdroop control, and is there any other name CPU FSB would be under??

    Thanks for the responses so far, guys! I will try this out at lunch (assuming I don't have to go out of town for work today).
  5. dont turn off vdroop control, fsb might be called termination voltage dont exceed 1.35 on it doubtful you will need 1.35 or more anyway
  6. Fair enough, thanks a ton. Will report back on this..
  7. Spixel, thanks man--took your first post as best answer (sans "turn off vdroop control") and it worked like a charm! thanks a ton man!!!

    FSB -- Memory = UNLINKED
    FSB -- 1800
    MEM -- 1600
    CPU v -- 1.3v

    Is that an acceptable voltage? Still appeared in the green in my BIOS options..I gotta prime95 it when I get more time, took a few reboots to get into OS stable but it seems great--idling 42C when I left--might drop a little more seeing as how that is a fresh layer of arctic silver 5 (like 24 hours since applied).
  8. RichardScott, thank you too! I would have selected both for best answer if I could; I gave it to Spixel since he was first response.

    Thanks both of you, certainly made my day!
  9. 1.3V is fine.
    Intel maximum recommended is 1.375. I'm running 1.46.

    Just make sure to install Prime95, and do a torture test (on blend and on small FFT), keeping an eye on temperatures. Do it for an hour. If you get errors, Vcore is still too low.

    If you're doing 4Ghz 100% stable in Prime95 on 1.3V, you're doing very well indeed!

    (Also regarding Vdroop, I have Vdroop control enabled. The reason being, low voltage causes my system to go unstable under load, but the apparent spike after coming off load (I haven't measured it, just read the Andandtech article) doesn't cause any problems, I'd rather have a tiny spike when changing from full load to idle than continually running my processor at a higher voltage when it's not needed. If there is no stability issues, then leave it off, I found it very useful personally).

    (Another also - you can set your FSB on your board, '1600' is 400Mhz, '1800' is 450Mhz. The FSB is quad pumped (4 lanes), so a 333Mhz quad bus is equivilent to a single channel 1333, so intel says things like 'FSB1333' .
    Your board is just letting you enter the pretty Intel number rather than the actual frequency. So if someone says 'set it to 460Mhz' just multiply it by 4 and you have your number for your nForce. Mine is 533 on my board, but would be called FSB2132 by Intel (or on your nForce).)
  10. Ahh thanks Spiders! This is probably the 4th or 5th post of yours that I've seen amongst the OC forums that has been helpful :) I appreciate the reply a lot.

    I will run Prime95 on that pig when I get back from the office. Just curious, what is your idle temp and cooling situation? I was stoked to see mine idling at 33C (only 3.6ghz stock voltage though) when I first installed the Xigmatek Dark Knight. I think I might want to reapply my AS-5 because I am not entirely sure I got it even since mine is idling 42C...although that is at 1.3v and 4.05ghz--will have to see! I also haven't let the AS-5 "settle" yet..

    I am leaving the vDroop control on--it has never caused me a problem in the past, unless I start running into issues I will let it ride.

    Also, thanks for the great FSB/nForce explanation--I've been building PCs for 8 years but am somewhat of a beginner when it comes to OC's over 15-20%. That was very helpful!

    Will be looking for your help in the future ;)
  11. Spiders, with 'Vdroop control' disabled I get stable voltages under load. With it enabled my voltage drops under load. Yours seems to work the opposite :D
  12. haha yeah I guess its based on weither the BIOS maker decided if it's 'Control VDroop On/Off' or 'VDroop On/Off'.

    Thanks for the credit there dirtdriver :) Good to hear I'm of use.

    I haven't really noticed much difference with AS5 settling, maybe 1C.
    I've got a Coolermaster NS520 with twin 92mm fans (which the motherboard usually only spins at 1/2 speed). I can't remember my idle temp, but Prime95 blend gets me 56C peak on the cores, and SmallFFT gets me 61C on the cores.

    I'm also benefited with an NZXT Tempest (7 fans standard). So case temp is usually pretty close to ambient temp. When I did the 61C test, ambient would've been around 20C.

    Also remember the E8x00 Core Temp sensors (Tjunction) don't read below 39-44C. So your idle is probably a lot lower than 42C, it just can't read that low.

    I have an E8500 but it's not a 'good' E8500, I've seen better overclocks at lower voltages with other chips.
  13. i was typing my first reply while he posted his :P
  14. Ran Prime95, 100% stable--temp peaked at 62C which is a bit higher than I expected, but it did not get any higher. This was all on Vista Ultimate 64..

    I have actually (since last night) reformatted and installed Win7 Ultimate 64--and I noticed my machine is running much more smoothly, and cooler as well. Don't know if it is just displaying more accurate temperatures now or if it is actually cooler. My GPU is idling 34-38C and cpu 38-39C. Very very pleased with that considering the 4.05ghz OC.

    Even whilst gaming on 1080p (dual monitors) L4D2 16xAF 4xAA settings max, my core temp never passed 55C :) I'm what you would call a happy camper.

    Thanks again everyone!
  15. glad we could help
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