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Overclocking CPU and RAM Issues

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  • Chipsets
  • Overclocking
  • RAM
  • CPUs
Last response: in Overclocking
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May 12, 2011 12:14:26 AM

I just got 2 gigs of DDR2 800MHz ram to add to my machine. When I added it, I began getting overclocking failure messages from my BIOS. I had my CPU running at 3.5GHz, but now I can't get it passed 3.2GHz without getting that failure message. Because of this, my ram is only running at about 730MHz instead of the regular 800MHz. What I'm wondering is, will this decrease of 70 MHz make any real change to the speed of my ram?

System Specs:
Asus M4A785-m Motherboard
AMD Athlon II x2 @ 3.2GHz (native 2.9GHz)
2 Gigs of Corsair XMS2 800MHz RAM
1 Gig of Lexar 800MHz RAM
Windows 7 Ultimate 32 bit

More about : overclocking cpu ram issues

a b K Overclocking
a b à CPUs
May 12, 2011 12:49:08 AM

Nope. In fact, you could decrease your RAM frequency to 400 MHz and still wouldn't notice the difference, unless of course you're doing benchmarking, then that 70Hz would show its tiny impact.

The biggest possible reason for the OC failure message is likely due to your RAM mixture. I'm going to assume that you know your way around your BIOS comfortable well and at least understand the importance of manually configuring your RAM settings in the BIOS.

If the above statement is true, then you must have manually configured the RAM settings in your BIOS to match either the Corsair specs, or the Lexar specs. That said, the only thing I see common between them is their frequency, which is the least important right now. Mixing RAM often results in undesirable experiences, such as your OC failure message. This is because of physical limitations; you know, the old adage "you can't fit a square block into a round hole."

The "Big Three" of RAM is Voltage, Timing, and Frequency. The stickers you see on the side of your RAM sticks are the manufacturers best operated specs. What this means is that these are the best values at which the RAM operated its best. Now, take that into consideration when you mix your RAM.

As an example, let's say the Lexar operates best at 800 MHz w/ 1.5 V and 4-4-4-12 timing/latency. Now, let's also assume that the Corsair sticks operate best at 800 MHz w/ 1.8V and 5-5-5-15 timing/latency. The problem here is that you cannot configure the BIOS to use two different settings at one time. So, because of this conflict in configuration, either the Corsair or the Lexar could become unstable, thus resulting in a lower OC than before.

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May 12, 2011 12:55:37 AM

...ensure the memory timings of the DIMMs are set to the settings of the slowest memory - i.e. the one with the HIGHEST timing values. The timing values are wait states. Lower values are better. Therefore the worst performing DIMMs will have the highest timing values.

Faster memory (i.e. with lower timings) will have no issue at all runner with worse timings (i.e. higher values for the wait states), but the reverse is generally not a good idea - i.e. attempting to use memory with slower timings at higher values to match a different DIMM.

That's a classic cause of system instaboility which is exactly the result you have got.
Correct the timings, volts and freq. and you should be all good :) 


Mixing and matching memory in this manner is generally not a good for the exact reasons you are experiencing - but it's a good learning experience to go through.
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May 12, 2011 12:56:09 AM

Thanks for the reply. Both of the types of ram are 800MHz and both are 1.8V. The Corsair ram is 5-5-5-18 and the Lexar is 6-6-6-18. Couldn't the motherboard just make them both run at 6-6-6-18 and everything would be fine?
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a b K Overclocking
a b à CPUs
May 12, 2011 1:03:02 AM

No, not exactly. Leaving the BIOS settings on [Auto] will allow the mobo to determine what settings to use, but since the timings aren't the same for both Corsair and Lexar, this can cause a problem when the mobo fluctuates the DRAM settings.
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May 12, 2011 1:05:06 AM

Alright. I'm not sure if I can manually set the CAS Latencies with my BIOS though, but I'll look around and see if there's something I can change on it.
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May 12, 2011 1:16:16 AM

Okay, I found out how to change the timings, so I think I'm good there, but I just have one more question. When overclocking, should I raise the voltage using the cpu overvoltage or the chipset overvoltage?
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a b K Overclocking
a b à CPUs
May 12, 2011 1:29:11 AM

Start with the chipset. Increase one step at a time. Meaning one preset value at a time. Save and exit. If stable, then you can try doing a higher OC on the CPU. If you do OC the CPU higher, and find your system unstable again, raise the voltages until you're stable again.

Also, disable any power saving features, like C1E. You don't want the mobo to control your fan speeds while ocing.

Edit: By the way, there is a limit as to how high you can increase the voltages and the CPU clock cycles. Also, you did not mention anything about an aftermarket CPU cooler. For overclocking, it is necessary to have an aftermarket CPU cooler, as the stock heatsink isn't large enough to dissipate the heat fast enough. Too much heat (from voltage increases) will damage your CPU, permanently.
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May 12, 2011 1:54:56 AM

I'm using the stock cooler, but even at 3.5 GHz, I haven't seen the temp go past 50 degrees celcius, and my CPU can take up to 70 degrees celcius, so I think I'm okay in terms of cooling.
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a c 242 K Overclocking
a c 139 à CPUs
May 12, 2011 9:31:47 AM

CPU can take up to 70 degrees celcius it's Ok for Stock cooler BUT NOT OK for healthy CPU and other hardware! you cannnot use this condition in daily, for better if you want get more up buy New good Cooler
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May 12, 2011 8:02:48 PM

Make sure to test your ram with a memtest86 boot disc and your CPU with prime95 when testing if the settings are working properly.

Ideally you want to run each for a period of 4-6 hours (mainly the memtest86).
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