Voltage: 1.8v vs 2.1v

Yes u have heard it right,2.1 is OC'd from the "The manufacture" there isnt any bad points in getting these RAMs.
Lower voltage makes the RAM work cooler but when u want to OC,its recommended to raise the voltage of the RAM,so with going with 2.1 Rams u may not need to raise but if u go with 1.8 then u may need to raise it to 2+

It will work fine, but memory rated for the same speed settings at 1.8V will run cooler, and overclock farther.

I agree about being cooler but not sure about better OC,because it really depends how much u can play with the settings

To OP,
Dont worry,there isnt any negative points in buying them and yes they can be more OC'd and also dont worry about the life either it will work for a long time

Go for a DDR2 800 RAM CL4 and u will be fine

Hey - similar RAM in consideration, but different situation. I have a Gateway FX4710 with a stock G33-chipset motherboard, and I recently bought 2x2 GB RAM of two types: Patriot Viper DDR2-800 and OCZ HPC Reaper DDR2-800, both of which are rated at 4 CL at 2.1V. However, I wasn't aware that the motherboard's voltage is only set at 1.8v, and since it's a OEM, there's no way to change the voltage in BIOS. I've been having problems with crashes if I use the OCZ and Viper in all 4 slots, but not if I only use the OCZ in two slots OR if I use the OCZ with 2 sticks of my original 667 RAM (in which case all the RAM is running at 667 instead of 800).

I'm wondering if OCZ HPC Reaper (http://www.ocztechnology.com/products/memory/ocz_ddr2_pc2_6400_reaper_hpc_edition) can actually sustain running at 1.8V if I put in 2 more sticks of them. So far they seem to be doing OK, but only with two sticks of them and two sticks of 1.8V RAM. I'm definitely returning the Patriot Viper sticks since they do not run, even by themselves, on 1.8V.

The other choice is to return everything and buy 8 GB of 1.8V 800mhz RAM at 5-5-5 timings, although I would prefer using the OCZ Reapers if they work. This is because I do plan on replacing my PC's motherboard in the future, and I suppose they are more versatile if I do decide to OC then.

Posted this elsewhere, but I hope I can get some more responses since I need to decide soon to return or not. Thanks - Tilted.