A-Tech 4GB (2x2GB) DDR2 667MHz DIMM PC2-5300 1.8V CL5 240-Pin Non-ECC UDIMM Desktop RAM Memory Upgrade Kit

Worked perfectly. What else is there to say.

This is an excellent product, I got two 4GB kits (4 modules), and all four worked just great, fully compatible with both Intel based computers where they were installed, I feel these memory modules are an excellent value, and revived a pair of 8+ year old computers, one of the computers is an Asrock G31M-GS based system, the other an Elitegroup 945GCT-M/1333 v3.0 with max RAM specs of 4GB (2 GB per slot) DDR2 667 MHz PC-5300, but I took a chance with these RAMs and they adjusted perfectly from 800 MHz down to 667 MHz (not all RAM modules can do this), in other words these modules can handle both 800 MHz PC-6400 and 667 MHz PC-5300. I would definitely like to try A-Tech's other RAM modules like DDR3 in the near future.It must be noted that (at least the ones I got), these RAMs can not handle the 533 MHz PC-4200 standard, this was not a problem for me, but if your motherboard/system is of an older type that can only accept this standard, then these modules won't work for you.Bottom line is that if your system/motherboard can handle 240-pin DIMM (Desktop PC), non ECC, DDR2, PC-6400 (800 MHz) or PC-5300 (667 MHz) RAM, then I would say there is a 99% chance these modules will be compatible with it.Tip, if for example you plan to get 4 GB of RAM,, get a kit (2 modules of 2 GB each), vs getting a single 4 GB stick, when you get a kit (two identical modules) you can benefit from dual channel, that way you can get a full 800 MHz speed vs just 400 MHz from a PC-6400 DDR2 when you use a single or an odd number of RAM sticks.

When I began to randomly get the dreaded "blue screen" I tested my old Optiplex 760's memory at startup by pressing the F12 key and, sure enough, there was a memory problem. Rummaging around on the web I found a description of the memory in this machine and did a search on Amazon. A huge number of choices came up but I picked this one based on the reviews about the reliability of the company and the support. It came a day early, was packaged professionally and the information on the package and the leaflet was obviously written by someone who was both knowledgable and proficient in English -- something that is becoming increasingly rare these days when instructions are often incomprehensibly written by a person struggling with a second language. There was a little card enclosed with installation hints, troubleshooting tips, a support number, and a believable promise of satisfaction. The memory installed without a hitch, fit perfectly in the slots in the computer, and worked flawlessly as well as passing the startup diagnostic tests when I ran them. I'll use A-Tech again!

Bought the 1 GB per stick version: 2GB kit (1GBx2) DDR2 PC2-6400 DESKTOP Memory Modules (240-pin DIMM, 800MHz) Genuine A-Tech BrandFor two sets of 1 GB pairs, the speeds matched, timings matched, and no problems detected through a 24 hour run of Memtest86+ (13 passes total through the 4 GB).If you're still reading then I suppose you may not know what you're fully getting (in terms of the product itself). A little backstory, DDR2 has been replaced quickly ever since DDR3 came out like 8 years ago. I don't think any manufacturer makes new DDR2 sticks for that reason, especially with DDR4 soon to repeat that history.Imagine hundreds of thousands of computer towers recycled/scavenged with those DDR2 DIMMs still lying within its chassis. Millions of obsolete sticks in storage boxes. Then for whatever reason, you've now ended up needing DDR2 again because you didn't want to let go of that HP/Dell/Acer/etc tower because "it still worked". It perhaps had 2 or 3 GB inside, and mix and match speeds, might even have been running in Single channel all this time, finally needing to set things right (instead of putting it out to pasture). I had a tower lying around with a AMD Athlon 64 X2, their first dual core CPUs. I had a choice between finding an upgrade to the CPU (which would have made the bigger difference, though not worth the effort), or at least making sure the ram was not the bottleneck (I could not even watch YouTube @ 1080p without hiccups).So what are you getting from "Genuine A-Tech Brand"? Refurbished DIMMs.In my case CPU-Z stated one pair came from lifetimememory, while the other pair is from Nanya (which included serial number/manufacturing date), That's definitely not a problem, ram is ram, so as long as it works at the listed specifications, which it does.After installing and running the checks, definitely a noticeable performance improvement from a 3GB, single channel setup (don't ask). YouTube @ 1080p worked fine at 30 FPS, but it still struggled for a full 60 FPS video (but a remarkable improvement). Netflix at least runs smoothly now, which was my main reason for keeping it and hooking up to a TV. Upgrading ram may not work for all scenarios, but for mine it's no longer ram, but a CPU bottleneck confirmed.Why knock off one star? They put those stickers right on top of the memory modules. For the 2 GB sticks they may have them back/front and is unavoidable, but the 1 GB sticks had an empty backside they could have stuck their stickers on instead. The old DIMMs I pulled out had the stickers peeling off because the stickers were on the modules as well (and these were OEM sticks). Wouldn't warranty be voided if the stickers were removed, even if naturally peeling off? Then again, by that time I hope to not be needing a replacement.

For the price, these are amazing. I use these to update my ReadyNAS Pro/Ultra 6 units. They are old NAS boxes, but with a memory upgrade they are still hugely capable as backup devices. Extra memory is a welcome addition and at this price a no-brainer upgrade. It IS a little of a pain in the bu** to get them installed on the ReadyNAS (just very tight space) but they work perfectly once installed. Have bought several sets. Will buy again of need arises.