Two ram slots not working

[ibrahim-traceur]

Hi guys, i have a gigabyte ga p43 es 3g and when i put 8gb ddr2 (4x2gb) the two first slots work fine but the others wont let the pc turn on. Thanks in advance

 

[serioussamik17]

1.Ensure the RAM s are fully compatible from the Memory support list in manufacturers website. It you are using 2 different 2x2 gb kits (same speed but different latency), they aren't compatible. The motherboard BIOS tweak can help you getting all the RAM's on a same page, but that is not always guaranteed. So be very sure on that.
2.Check each RAM's individually. Ensure all the RAM s are working fine.
3.Check the RAM settings in the BIOS and see if the speeds/latency/voltage are set correctly (try getting help if you are not sure).
4.You may update the motherboard BIOS if none of the above is the case, but again try seeking expert's help in doing so as this is a risky process and any error while updating BIOS can render your PC useless.
5.There is a possibility that the RAM slots are damaged, but that is rare.

 

[Calvin7]

8gb ddr2 (4x2gb)

Looks like four random DDR2 modules. Try Brand, Model#, Part#, And or Link

The P43 Chipset has a MCH (memory controller hub) that would require increased voltage if populating all memory slots (safe limits for the MCH which is 1.4v) and memory speed may be limited to 667MHz when using all slots.

 

[ibrahim-traceur]

Im using this generic ram https://www.google.es/amp/s/m.aliexpress.com/item/32872021004.html with a Xeon X5460 i dont know how to tweak it in the bios

 

[Calvin7]

MCH/ICH
MCH Core
The default is Auto.

 

[ibrahim-traceur]

Ive changed the Mch core to 1.4 V but still the problem

 

[serioussamik17]

Go to the memory config in the BIOS and try changing voltage to 1.8v (timing 6-6-6-18) if you are populating all the RAM slots. Try 1.4v if you going lower clock at 667 mhz as @Calvin7 rightly mentioned. You can also use timings like 5-6-6-18 @677mhz on 1.4V.
From the link you have shared it shows me:

Brand Name: PLEXHD
Application: Desktop
Frequency: 800Mhz
Type: DDR2
Item Condition: Used
Memory Voltage: 1.8V
Cooling Fin: No
Warranty Time: One Year
Interface Type: 240pin
The value of CL: 6
Function: NON-ECC
Memory Frequency: 800 MHz
Sequence: 6-6-6-18
Combination Form: Single
Model Number: 2GB
Package: No

But then again, these are non ecc RAM's with no capability for error checking, so if exists any variance in timing ,latency and voltage it cant be overriden. And your CPU is also a server level one (LGA 771) and your motherboard is LGA775, so unfortunately if there is a compatibility issue that can't be ironed out, you have to stick to 4gb.