P-7811FX 8GB Ram Upgrade - Need Help

I bought Corsair #CM3X8GSDKIT1066 8GB DDR3 PC8500 1066Mhz Ram, 2each of 4GB modules. After installation, laptop would not boot. Lights illuminated on the keyboard, but display was blank, no beeps, no blinks, no erros. Like the bios would not start. I tried each module individually, and with only one of the 4GB modules in laptop ran fine. Each module worked individually.

Call Corsair and they said the bios timing was probably too fast and to slow it down. But don't see a way to do that with the 9C.23.00 bios, the latest for this laptop.

For those of you who have installed 8GB, what brand and model number did you use. Were there any problems?

With regard to the bios, does anyone know a way to control Ram timing?

 

If each stick works individually then it most likely is not the timings but the comand rate associtated to the timing. All P78xx bios versions to my knowledge want to run the memory as comand rate 1T. Some cheaper memory may not allow this with multiple sticks even though the SPD tells the bios it can.

If this is the case you are better off returning the memory...............

 

I was led to believe Corsair was high quality, but apparently they got something wrong here. Can you recommend a manufacturer that you think would work? Is there any advantage, or increase of success, by going to the 1300mhz memory.

 

Newegg.com - Mushkin Enhanced Essentials 8GB (2 x 4GB) 204-Pin DDR3 SO-DIMM DDR3 1066 (PC3 8500) Dual Channel Kit Laptop Memory Model 996644

Bought this as a personal Christmas present, and they've been working fine ever since. I specifically AVOIDED Corsair's SODIMMs because the reviews were pockmarked with more than enough poor and mediocre reviews to make me uncomfortable.

 

Thanks for the recommendation. I've already ordered the Crucial ram as they give a full refund guarantee. Newegg has a 15% restock fee. I'll report if it works. If not, I'll go with your recommendation.

 

I called Corsair tech support. They said that because each module would work independently that there was nothing wrong with the ram. The problem was a compatiblity issue with using 2 modules. Corsair did say to lower the ram timing in the bios, but my bios doesn't give me the option. So Corsair said to send it back. I'm sure Corsair makes good memory, my research indicated they were one of the better brands, but in the P-7811FX it just didn't work.

 

I called Corsair tech support. They said that because each module would work independently that there was nothing wrong with the ram. The problem was a compatiblity issue with using 2 modules. Corsair did say to lower the ram timing in the bios, but my bios doesn't give me the option. So Corsair said to send it back. I'm sure Corsair makes good memory, my research indicated they were one of the better brands, but in the P-7811FX it just didn't work.

 

I installed the Crucial 2x4gb PC-8500 1066Mhz and - IT WORKED.
Laptop booted as usual, no problems, and system is now reading 8GB of ram.
Hurray!!! Now to see if it makes an operational difference.

Thanks for all the advice.

PS, The ram timing on the P-7811FX is 7-7-7-20, which is what the Crucial is also rated for. The Corsair was as well, but for some reason the Crucial can handle the T1 single cycle speed while the Corsair did not. I don't understand why one and not the other, but glad I finally got it working.

 

Some memory sticks are fine on 1T with a single stick but when you increase the banks with 2 sticks the memory at 1T fails. This is usually true of the higher capacity raam too. Where 2x2GB would work fine the increased banks or bank size will fail with the increased memory size. It isn't a problem with the ram just a limitation and if the bios can not recognize the limitation you get the fail to boot problem you had.

I have yet too see a P78xx or P79xx run over 1T so I highly suspect our bios makes memory that needs this uncompliant. Not sure if this though becomes a bios or chipset, even a chipset revision, issue..................

 

Tanware,
Thanks for your help. You really know the inside of these machines.

Can I ask, are we stuck with the Phoenix Bios. It would be great to download one that had more functions and ability to be manually controlled.

For my next machine, do you know a Bios manufacturer I should look for that would let me have control of memory settings, temperature settings, clock speed, etc.

 

There are no custom bioses avaiable. There are hacked for the EIST but that is about it. If you really needed control you could change the SPD of the ram but it yeilds not too much.

I took my 2x2GB sticks and set the SPD to CAS 6 JDEC standard for 1033 memory but it yeilded very little other than some PERCIEVED snappyness. Nothing I could document. Now this though was with 6 meg L2 chips, the lower cached chips may actually bennefit from CAS 6.

Needless to say since there was no real world benefit I could see with the old memory I ahven't tried to burn these over to CAS 6. Essentially why take the risk with the chips when there is no real world advantage.

Now for the right amount of money someone would do a bios but the amount would be insane and there are not enough machines out there to recoupe the costs involved.....................