Sign in with
Sign up | Sign in
Your question

FSB Wall.... anyway around it ?

Last response: in Overclocking
Share
January 1, 2009 10:15:09 PM

Hello, I have from my understanding reached my max overclock at 3.75ghz, this to me is somewhat disappointing considering I bought an E8400. Its weird, as soon as I clock my FSB over 417 mhz it wont post, no matter what I do to the voltage settings, I maxed out the GTL reference voltage, upped the FSB, north bridge and south bridge voltages along with obviously the vcore upped as well, but no matter what it still wont post. I cant really eliminate the memory as the culprit because I have it set to the lowest multiplier possible, and im still at 840 mhz. Im sitting at 3.75ghz with a Vcore of 1.25 and I beleive it could be lowered. I personally think that it is a mother board issue as it is rated for only a 1600mhz FSB, because my processor seems to be extremely stable even at low voltages.
Any suggestions ? comments ?

More about : fsb wall

January 1, 2009 10:59:08 PM

not every chip is the same, your chips has a max of E8400, nothing you can really do about it if you've already tried everything...


Loosen the memory timings up if you haven't and see.
a b à CPUs
January 1, 2009 11:06:12 PM

Hard to help without posting your system specs. What mobo, RAM, etc.
Related resources
January 1, 2009 11:13:46 PM

it could be a FSB hole and not the wall itself. 417mhz is still in the moderate range. 450+ is starting to get up there. i wouldnt use 450+ myself (i have a quad so cant clock as high), but there are certain holes in FSB that would refuse to post no matter what. from what you are stating, your memory is only at 840mhz and your vcore is at 1.25 when 1.365 is the max rated for the 45nms'. you still have a lot of headroom left concerning vcore and ram.

a 1600mhz mobo could handle 1700mhz with no probs. but like you said, it could be a lot of things (maybe ur mobo isnt' a good OC-er). your chip sounds okay to me, but it could be other factors. i'm going to use my Q9450 as an example. around 450 FSB, it wont post at all, not all the way until around 472ish for me but i would have to up the vcore considerably and loosen my timing on the rams to 5-5-5-20 or 6-6-6-20. that is a BIG gap of a fsb wall/hole. so if you want, you can try a bit higher, but how far is your discretion. just my 2 cents :) 
a b à CPUs
a b K Overclocking
January 2, 2009 3:17:19 AM

what is your fsb termination voltage set at? For over 400fsb try 1.3

And yes system specs would definitely help
January 2, 2009 7:24:05 AM

ya fsb HOLE i say.
January 2, 2009 10:12:53 PM

Sorry bout the system specs, here they are

Asus P5QL
4 GB Kingston cheapy DDR2 6400 (5,5,5,18,2)
C2D E8400
Zalman CNPS 7700 CU
X1900XT
Enermax Liberty 620watt


This is what I did last night and didn't find much luck, I went in random increments all the way upto 470 FSB, loosened all of my memory timings to 7,7,7,20,2 upped the memory voltage to 2.20, maxed the FSB termination voltage, maxed NB voltage and SB voltage... still no post after 418. So then I tried setting it back to the stock frequency, and I switched my memory multiplier to DDR 1000, booted up no problem, set the FSB back to 416, put the FSB strap down to 266, which inturn made my memory just tip over 1000mhz, wouldnt post. Its definitly the board, not being able to handle the extra load.
January 5, 2009 1:09:30 AM

I guess Ill have to settle for 416MHZ bus speed, it still works pretty damn good and bottlenecks the hell outta my X1900XT, source pings off of 360FPS in D2 tunnels... 1280x1024 @ 4xMSAA, 8XAF all on high. So I suppose its fast enough haha.
January 5, 2009 1:17:59 PM

Maybe it's just me, but i'm surprised no one has mentioned the fact that it might be your cheapy DDR2 6400 isn't overclocking well...
a b à CPUs
a b K Overclocking
January 5, 2009 1:47:52 PM

RAM speed is linked to FSB speed. So UNDERclock your memory first, so you eliminate that as a factor in your Processor overclock. Then try again.
a b à CPUs
a b K Overclocking
January 5, 2009 1:52:02 PM

I told him to do that, apparently he didn't want to try it, lol
January 5, 2009 10:13:44 PM

Cant under clock the ram at that clock, the mobo only gives the DDR667 option as the lowest multiplier which equals around 840 mhz at an FSB of 420. The only thing I could do and did try was relaxing the timings and maxing out the voltage. But the ram shouldn't have been the problem because at 3.0 GHZ I was able to run the ram at DDR1000, and it posted just fine. Unlike when I hit around 420MHZ on my FSB and my ram only touching around 840mhz.
January 5, 2009 10:31:28 PM

EDIT** I tried to get the computer to post at 419, would not post what so ever, so I gave the ram 2.20 volts instead of 2.10 and it posted, so while the ram at 3.0 ghz seemed to be fine running at 1000mhz, it isnt fine running at 439 without 2.20 volts. Seems asthough I am going to be needing some better ram.
a b à CPUs
a b K Overclocking
January 6, 2009 3:30:39 AM

sry mike I confused this thread with another one, lol.

I didn't tell you to do that, hehe

January 7, 2009 2:48:22 PM

Its cool man, appreciate the input.
a b à CPUs
a b K Overclocking
January 7, 2009 3:52:57 PM

Mike, I've had an E8400 (E0) for about a week now with an Asus P5KC (I know) old P35 mobo. When I first installed it with DDR2-800 ram I was only able to reach 3.825 GHz. Replaced the ram with DDR2-1066 and have it humming along at 4.00 GHz (500X8) @1.280 Volts, NB 1.4 Volts, Ram underclocked to DDR2-1000 @2.1 Volts. Chips and boards do vary but with your board and processor you are probably correct about it being a Ram issue.
January 7, 2009 5:26:51 PM

Btw, when they mentioned underclocking the ram, they simply meant bringing it back to a 1:1 ratio - but you're over 400mhz anyway - so your cheapy DDR2 is now running at 838mhz (38mhz more than it would like to) and I wouldn't be surpised if thats what was holding you back. You can pickup a couple sticks of either 1gb or 2gb ballistix or corsair running at PC8400 for around 100$
January 8, 2009 1:42:38 AM

Yea I figure its the cheapy ram, oh well I suppose 3.75GHZ will have to do for now. I figure my processor is good for 4.0 GHZ, its only running 1.26 volts right now, perfectly stable, I could probably bump it back a bit but right now heat isn't an issue as it gets to around 54 full load in prime 95. Ill most likely buy some new ram when I upgrade my gfx card as it is getting a tad old by now. Right at the moment, the processor does 1M in super pi in 12 seconds flat, so I figure its a pretty quick machine.

Thanks to everyone who replied and gave me good input.
!