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PC2 - 8500 1066mhz being read as PC2 6400 800mhz

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  • Memory
  • DDR2
  • RAM
Last response: in Memory
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May 19, 2011 1:37:11 PM

Hi Guys

I have had this problem for a while and have been unable to solve it - i have 4x2gb DDR2 PC2-8500 Kingston Hyper x @ 1066mhz installed in my computer, but when i look at the system specs using a program like CPUID or PC Wizard 2010, i find that the ram is only being read at 800mhz as PC2-6400 @ 800mhz.

I have changed the ram settings in bios to the following:

5-5-5-15 latency timings
2.2v for the ram
and i have set the ram as DDR2 1066mhz in bios.

But, none of this seems to change anything. The RAM is 100% compatible with my motherboard, so i see no issues.

Any ideas?


Spec:
w7 x 64
Asus P5q PRO Turbo
Intel Core 2 Quad Q6600 @ 2.4ghz
4x2gb DDR2 PC2-8500 Kingston Hyper x @ 1066mhz, 2.2v, 5-5-5-15
Various Sata harddrives (4TB)
600w OCZ Stealth 2 Extreme PSU
nVidea GTS 250 @ 1024mb.

Link to RAM:

http://www.google.co.uk/products/catalog?q=kingston+hyp...

Link to ASUS RAM reccommendations:
http://www.asus.com/Motherboards/Intel_Socket_775/P5Q_P...

Thanks in advance

More about : pc2 8500 1066mhz read pc2 6400 800mhz

a b } Memory
May 19, 2011 4:14:12 PM

There is no "problem". Your RAM is doing exactly what it is supposed to do. The performance readings are due to the FSB and the FSB/DRAM ratio.
Look, your Q6600 has a clock speed of 2.4GHz, on a 9 multiplier. 2400 / 9 = 266.66. So your FSB in BIOS is reading ~267.
But the FSB is 1066. Look at CPUZ, what is the FSB/DRAM ratio? 4:5 if I remember right. So 266 x 4 = ~1066. but because of the ratio your RAM is at 800. Well, 800 x 4 =3200, but you have DDR@ Dual-channel RAM, so 3200 x 2 = yup, there's your 6400.
Setting higher DRAM frequency in BIOS won't work until you raise the FSB. I have heard of guys getting 3.33GHz by raising the FSB to 370 @ 1.36v. But bear in mind you will almost certainly need to raise the Northbridge voltage - you could try 1.3v and see if it goes red in BIOS (it will tell you).
Now that you have those extremes, you can play around with lower voltages and frequencies if you want. You will get much more performance from higher FSB than you ever will from higher DRAM frequencies, which, in fact, might lower performance. What you have done with timings is the way to go, but still, you probably did not get more than a 1% gain.

I say, leave the RAM alone. Play with your FSB if you want to have some fun but remember you are going to make a lot of heat in there, so don't do anything until you get some aftermarket cooling.
May 19, 2011 5:59:37 PM

Noworldorder said:
There is no "problem". Your RAM is doing exactly what it is supposed to do. The performance readings are due to the FSB and the FSB/DRAM ratio.
Look, your Q6600 has a clock speed of 2.4GHz, on a 9 multiplier. 2400 / 9 = 266.66. So your FSB in BIOS is reading ~267.
But the FSB is 1066. Look at CPUZ, what is the FSB/DRAM ratio? 4:5 if I remember right. So 266 x 4 = ~1066. but because of the ratio your RAM is at 800. Well, 800 x 4 =3200, but you have DDR@ Dual-channel RAM, so 3200 x 2 = yup, there's your 6400.
Setting higher DRAM frequency in BIOS won't work until you raise the FSB. I have heard of guys getting 3.33GHz by raising the FSB to 370 @ 1.36v. But bear in mind you will almost certainly need to raise the Northbridge voltage - you could try 1.3v and see if it goes red in BIOS (it will tell you).
Now that you have those extremes, you can play around with lower voltages and frequencies if you want. You will get much more performance from higher FSB than you ever will from higher DRAM frequencies, which, in fact, might lower performance. What you have done with timings is the way to go, but still, you probably did not get more than a 1% gain.

I say, leave the RAM alone. Play with your FSB if you want to have some fun but remember you are going to make a lot of heat in there, so don't do anything until you get some aftermarket cooling.



wow you are good bro ...thats the pepps we need in here ...good job
May 19, 2011 6:14:48 PM

Okay! Thanks again NWO!
!