Which two RAM slots to populate on a 4-slot system?

[ajkula66]

The question is pretty self-explanatory, but...let me put it like this:

Presuming a 4-slot system such as W520, which two slots should be populated for optimum performance?

TIA in advance for any wisdom that you can share.

[mpcook]

I believe I got this originally from the Lenovo forum where there is a picture as well. It applies to W510 and W520.

When buying additional memory DIMMs for ThinkPad W510 systems, Lenovo recommends that you populate the memory DIMM slots in the following order to take advantage of the best system performance. This memory DIMM slot order is optimized for dual channel memory configurations.

For ThinkPad W510 systems, populate memory DIMM slots in the following order:
• For systems with only 1 memory DIMM installed, populate DIMM Slot 0 (the upper memory DIMM slot underneath the keyboard).

• For systems with 2 memory DIMMs installed, place the largest memory DIMM capacity into DIMM Slot 0, and place the second memory DIMM in DIMM Slot 1 (the memory DIMM slot under the DIMM door on the bottom of the system nearest the optical drive).

• For systems with 3 memory DIMMs installed, place the largest memory DIMM into DIMM slot 0, place the second largest DIMM in DIMM slot 1, and place the third memory DIMM in DIMM Slot 2 (the lower memory DIMM slot underneath the keyboard).

• For systems with 4 memory DIMMs installed, place the largest memory DIMM into DIMM slot 0, place the second largest DIMM in DIMM slot 1, place the third largest DIMM in DIMM Slot 2, and place the fourth DIMM in DIMM Slot 3 (the memory DIMM slot underneath the DIMM door on the bottom of the system nearest the 1394 port).

Essentially, populate the ram in pair (slot 0 + 1 or slot 2 +3) to get the best dual channel performance. Also, make sure you get ram pair that has the same speed rating, i.e. 1333 MHz DDR3 ram should pair with 1333 MHz ram, and 1066 MHz ram with 1066 MHz ram, in either slot 0+1 or slot 2+3.

[mpcook]

On my system, when the memory was not installed per these instructions, it would either not boot, or it booted but I got memory errors depending on what was installed where (W520 QC).

[ajkula66]

^^^^^^^

Thanks for the help, Mike.

Highly appreciated.

[mpcook]

Your welcome. I emailed the pic to you (easier for me).

[MisterB]

My newly acquired W510 has two 4gb sticks under the keyboard and boots with no problem. It looks like I'll get a performance boost if I move one of them to slot 1. Nice to know.

[Tasurinchi]

I believe I got this originally from the Lenovo forum where there is a picture as well

Yep, this is it