I have an aging but still strong ~10yo computer. It's running on an Asus P4PE. I never needed to change anything except upgrading the graphic card, and I would like to keep that way as long as possible.

I was recently plagued by RAM problems. I was running 2x1GB, in the 2 slots that are closest to the CPU, as required by the manual.

After many verifications (testing both sticks individually as well as a 500GB spare stick, as well as testing all slots individually), I was able to identify one of the 1GB stick as faulty... but also that the first slot (i.e. the one closest to the CPU) is defective. Slots 2 and 3 are OK.

I would like to know if I can run the computer safely without using the first slot. Can I put 2 1GB sticks in slots 2 and 3? What about running 1x1GB + 1x500MB, does it play a role to have different capacities in one slot or the other? (I would like to use 1.5GB for the time being).

The manual say the following:

2.5.2 Memory configurations
You may install any DDR DIMMs with 64MB, 128MB, 256MB, 512MB, and
1GB densities into the DIMM sockets.

Warning! Use only the following combinations to install DDR DIMMs. Otherwise,
the system may not boot up:

(Rows 0&1) (Rows 2&3) (Rows 3&2)
SS/DS -------- DS -------- None
SS/DS -------- SS -------- SS

SS - Single-sided DIMM
DS - Double-sided DIMM

1. DDR DIMM sockets 2 and 3 share the same rows, so if you install
a double-sided DIMM into DIMM2 socket, you must leave DIMM3
socket empty.
2. You may install single-sided DIMMs into DIMM2 and DIMM3
sockets at the same time but neither one can be x16 DDR module.
3. Double-sided x16 DDR DIMMs are not supported on this motherboard.

What does this mean exactly? The 1GB I have is Kingston, this one: http://www.valueram.com/datasheets/KVR333X64C25_1G.pdf

Is it single or double-sided?

Would I be able to still run 2GB RAM using slots 2 & 3? Or maybe 1GB + 500MB?

Thanks in advance!