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Help with Phenom 940 and Ram

TomH

TomH

TomH

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Joined
13 May 2006
Posts
51
I've just finished building my new system, PhenomII 940, Asus M3A79T Deluxe and 4GB of Corsair PC8500 (1066) memory, but the memory is only showing as 800 Mhz instead of 1066Mhz, could anybody advise the best way to change it in the bios to 1066, I haven't overclocked anything just left everything at default settings for now, I'm using 2 sticks of memory btw.

Tom
 
<chuckle> they hide the setting away from casual view

BIOS: Advanced->Jumper Free Configuration

First change AI Overclocking to [Manual ]

Now, see post 6 for the easy option or:

The display changes to reveal all the clocking goodies. The one you want is FSB Frequency, set it to your desired RAM speed divided by 4. eg my ram speed is 1066 so FSB Frequency equals 1066 / 4 = 266.5 so set [266] and you are ALMOST done.

Since the FSB speed has changed you should also change the three other multipliers that make reference to it (perhaps you can leave these at AUTO ? I forget ). These are:

Processor Frequency Multiplier
Processor-NB Frequency Multiplier
CPU-NB HT Link Speed

If you don't change these then you will be overclocking both you CPU and memory interface, plenty of time for that later. For now change:

Processor Frequency Multiplier to [11]
Processor-NB Frequency Multiplier to [7]
CPU-NB HT Link Speed [1.6 GHz]

So:
11 * 266 = 2926 which is as close to the original 3GHz as we can get

7 * 266 = 1862 which is close to the default 2GHz speed we started with ( I think the default is 2GHz ?? It's close enough ;) ). A value of 8 (8 * 266 = 2128 ) should work fine too.

The 1.6 GHz HT Link Speed setting is misleading, it is calculated assuming the FSB speed is set to 200. Annoying. The actual value you end up with is [HT Link Speed] / 200 * FSB. So, setting this to 1.6GHz should give 1.6 / 200 * 266 = 2.1GHz.

Asus M3A79T BIOS 0703 Advanced->Jumper Free Configuration:

x3OC1Bios.gif


Ok, now reboot, if all is well use something like CPUz / AMD AOD to double check the settings.

If Windows fails to load then reboot and double check the BIOS settings, perhaps switch everything back to AUTO, reboot then start over.

If the PC fails to get as far as loading Windows then panic... for about 10 seconds, press the Power button until the PC turns off, count to 10 and turn the PC back on. The M3A79T is very nice in this respect, it should recognise the failed startup and prompt you to press F1 to enter the BIOS so you can review / correct your settings, the only side effect of this is that it may return all settings to whatever safe defaults it thinks are necessary.

... Well, that's the basics, please DO NOT just copy all the settings in the pic. as you may end up with a dead processor. Especially do not go changing the voltage settings until you want to overclock the CPU and you have a good idea of the the maximum voltages and temperatures you can use before the smoke comes out.

Apologies if my information on the default NB Frequency and HT Link Speeds is incorrect. The above values should work without issue but perhaps someone will confirm or correct me on these if you wish to wait ?
 
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Heh that's overclocking the FSB, it doesn't change the RAM timings as such. There's an option within the M3A79-T BIOS that you can change the memory timings directly. It's in the options underneath the screen you've posted.
 
Thanks NightmareXX, I know the one you mean, but I've never used it ;)

In the above. You still need to select AI Overclocking [Manual ], scroll down a little and select DRAM Timing Configuration, then select Manual for Memory Clock Mode which allows you to directly enter a base memory speed which is half the target speed, so 1066 = [533], 532 on my system for whatever reason. All the other clocks and multipliers then take care of themselves (?)

That's a lot more straight forward, avoiding all the other multipliers :) , but I know human nature and once Manual mode is selected and all those settings are revealed curiosity will get the better of some. I'll leave post 4 as is, it's not a bad introduction to the wonderful world of PII clocks and multipliers :cool:
 
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Thanks ecat, that is some good information you posted there, I tried just changing the memory settings as you suggested to 533Mhz but it now shows in CPU-Z as 267Mhz where as before it showed as 400Mhz, it also shows as PC 6400 instead of PC 8500, any idea what is causing that?

Tom
 
Interesting, as I said I've never tried doing this the easy way.

In CPUz you see the 267MHz value on the CPU page ? Try looking at the Memory page, FSB: DRAM is the memory divider, if this is 1:2 then you should be ok ( it appears to work like this: (267 * 2) @ DDR2 = 1068 ). Previously at 800MHz I'd guess FSB: DRAM was 1:1 giving (400 * 1) @ DDR2 = 800... Ok, I'm guessing here and from doing so from memory :(, but this looks about right and the numbers add up.

Edit, love the way FSB: DRAM ends up with a grin FSB:DRAM .
 
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In CPU-Z on the memory page it now shows as DRAM frequency 267.6Mhz and FSB:DRAM as 3:4, don't know if this helps.

Tom
 
This first paragraph is nonsense (ecat 03/03/09)

You could poke around the BIOS and the web looking for memory divider and try to find a way to change the 3:4 to 1:2. The current 3:4 setting combined with 267MHz should give about 713MHz DDR speed (?), it looks like the BIOS is trying to keep you near 800.

I don't have an answer for you off the top of my head, well you could reset everything to default/AUTO, restart, and try the hard way :D, but if you have no joy by the end of the day I'll see what I can find out when I get back home.
 
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Is this 4 x 1Gb or 2 x 2Gb

If the former you will not be able to run at 800Mhz due to a limitation with the current AMD architecture for this CPU.

Only way to run 4Gb at 1066 is to have 2 x 2gb in separate channels. If you are using 2 x 2gb then don't have them in adjacent slots.
 
The code is not on the QVL list at all for either 800Mhz or 1066 Mhz, don't know if that makes a difference or not.
 
Oh well, when all else fails download and read the manual:

Memory Clock Mode [Manual]
Options [400][533][667][800][1067]

So, it looks like you can forget all about memory dividers and such. Try selecting the [1067] option and see how things go :doh:
 
You could try searching on the asus, corsair or amd forums for someone using the same combination.

I had a lot of problems with the OCZ gold 4gb kit and returned it due to 'motherboard incompatibility' due to not being on QVL. Replaced it with the Reaper version and that worked @ 1066 straight out of the plastic wrapper.
 
... on the other hand I've had no problem with the OCZ 8500 4GB gold kit + m3a79t, it's happy at 800, it's happy at 1066, I've had it up to 1104 @ stock timings, 2.1v. Still, fore-warned is fore-armed :)
 
I'll try the Corsair forums, like you say somebody might just be using the same combination, other than that I'll probably just have to live with it.
 
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