DDR2 RAM voltage and OC

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wert56boom

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Hi, this is my first post in this forum, but i have been visiting techspot for for quite some time now and i have to say it is nice place to learn and read about computers.

I am about to get q8400, to replace my e4400. I have overclocked e4400 (3.43 ghz)and i am going to overclock q8400 when i get it. But the problem is my Ram. I have 3x1gb ddr 800mhz ram, two sticks of patriot and one transcend.

To be sure my Ram will work fine with q8400 i tried them out to see how high i can push them. On my dissapointment i just cant get them stable higher then 415 fsb. Which doesn't make much sense as i have been running them at 860 for some time and even 890 mhz on auto voltage.:confused: If i change(increase) timings system doesn't start and it says oveclocking failed, right now i am at 2.1 volts. Default 1.8 i think. The only stable timings are 5-5-5-18 :mad:

I read this about ddr2 ram
According to JEDEC[1] the maximum recommended voltage is 1.9 volts and should be considered the absolute maximum when memory stability is an issue (such as in servers or other mission critical devices). In addition, JEDEC states that memory modules must withstand up to 2.3 volts before incurring permanent damage (although they may not actually function correctly at that level). (Wikipedia)

So could i push my cheap ram to 2.3 volts?

Please don't tell me to buy different ram or CPU. I have Asus p5kc MB, and i read somewhere it doens't like overclocking ram.

thnx for help
 
Hi wert56boom
if you are OC'ing via an FSB push, the weak link can be any component or chipset. the fact that you have mis-matched ram modules could be a likely suspect. is you are at 2.1 now...I would stop just shy of guaranteeing you that 2.3 will not give you stability, and probably burn up your ram. A few of the high performance brands have an overvolt guarantee up to 2.1v Take what it will give you @ 1.9v and call it good unless you are prepared to replace it.
I would try removing the lone Transcend module and see if that yields better results. you will lose 1 Gb fd ram, but gain dual channel until you get different memory. and it will let you know if the mixed modules are the limiting factor. The 880-890 Mhz you are referring to is the effective DDR rating 2x400Mhz = 800Mhz DDR2
 
Both of your ram modules are in the "budget" isle of ram purchases. This is one reason I came to love the architecture of the i7, I was once in the situation you are in, and it becomes difficult trying to figure out if the ram's the problem(which is most likely the issue here) or the chipset itself.

Consider the possibility that the two types of ram have different max timings, i.e your transcent can only do 5-5-5-18 while your patriots can go even lower, and they both work natively at different voltages. I can see a little conflict in there somewhere.
 
Thank you guys for reply, I am running them at 412 right now on auto volts and they seem stable. Based on that, i'll be able to push q8400 to at least 3300 Mhz and it should give me a performace boost compere to e4400 @3.43 Ghz.
 
412 FSB shouldn't be much of an ask for a Q8400, and should be do-able on stock Vcore.
Mix and match RAM is probably not the best approach for OC'ing, so I'd leave the memory divider at 1:1 (DDR2-825), especially since the RAM you have (at least the lowest specced part) is CL5 which implies that it is low-binned (budget). Running at a higher bandwidth is realistically the realm of CL4 (ideally 4-4-4-12) binned modules.
Remember that the JEDEC specification for DDR2 is 800 -anything higher than that, whether it's the manufacturer (XMP, EPP) or user's profiles is overclocked by definition.
As for overvolting...from personal experience anything over 0.1v over the particular modules' specification* is russian roulette. If the modules need more than that then a commensurate voltage bump for the MCH (northbridge) is also usually needed, which if left to "Auto" settings usually means a lot more voltage than is required, which in turn generates a lot of heat that the chipset heatsink needs to dissipate.

The JEDEC specification you listed (2.3v), is primarily the province of modules tailored for nVidia chipsets, some are rated at 2.3 -2.35v.(the latter figure is EVP (Extended Voltage Protection)- basically a "do not exceed" threshhold). nVidia SPP's (northbridge) can handle a much larger voltage than can Intel chipsets such as your P35.
 
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