I'm contemplating increasing my memory from 4 gb to 6 gb of DDR2-800 RAM and want to know what type and specs on the memory I should buy to add so it all plays nice together and does not decrease performance by upgrading? The system is an HP that can handle up to 8 gb RAM. My system is currently Vista x64, Q6700 2.66 ghz processor and the 4 gb of memory consists of 4 x 1 gb modules. My thought is to leave 2 x 1gb modules and add 2 x 2gb modules to give me 6gb total. Here are the details on the existing memory taken from PC Wizard 2008.

General Information :
DIMM0 (BANK0 ) : 1024 MB - DIMM
DIMM1 (BANK1 ) : 1024 MB - DIMM
DIMM2 (BANK2 ) : 1024 MB - DIMM
DIMM3 (BANK3 ) : 1024 MB - DIMM

Information SPD EEPROM (DIMM0) :
Manufacturer : MOSEL
Part Number : V916765K24QCFW-G6
Serial Number : 02A72A8C
Type : DDR2-SDRAM PC2-6400 (399 MHz) - [DDR2-800]
Format : Regular UDIMM (133.35 x 3)
Size : 1024 MB (2 ranks, 4 banks)
Module Buffered : No
Module Registered : No
Module SLi Ready (EPP) : No
Width : 64-bit
Error Correction Capability : No
Max. Burst Length : 8
Refresh : Reduced (.5x)7.8 µs, Self Refresh
Voltage : SSTL 1.8v
Prefetch Buffer : 4-bit
Manufacture : Week 17 of 2008
Supported Frequencies : 333 MHz, 400 MHz
CAS Latency (tCL) : 4 clocks @333 MHz, 5 clocks @400 MHz
RAS to CAS (tRCD) : 5 clocks @333 MHz, 6 clocks @400 MHz
RAS Precharge (tRP) : 5 clocks @333 MHz, 6 clocks @400 MHz
Cycle Time (tRAS) : 15 clocks @333 MHz, 18 clocks @400 MHz
Min TRC : 20 clocks @333 MHz, 24 clocks @400 MHz

Ideally, try to find 2x2gb sticks that run at the same voltage (1.8) and timing (4/5/5/15). If they're off, it'll still work.

It's 4-5-5-15 @ DDR2 667 and 5-6-6-18 @ DDR2 800 Download and run CPUZ and click the memory tab to see what it is currently running at.

Thanks everyone. Checked the exact timing as suggested. Looks like it shows 6 6 6 18. I assume I'm misreading something and that first 6 should be a 5?

Is there a particular brand and type for that brand that would be a good match to the existing Mosel memory or at least a brand and type that works well for upgrading easily at that voltage (1.8) and timing (5-6-6-18 @ DDR2 800 - assuming that is correct)?

Any suggestions on this last question?


Thanks

This would be your best option.