Corsair TWIN2X2048-6400C5DHX XMS2 DHX 2 GB 2 X 1 GB PC2-6400 800Mhz 240-pin DDR2 Dual Channel Memory Kit

I had Corsair's other memory modules and they failed but the original DHXs were still functioning and so ordered these! PROBLEM: The Customer Rep told me I could purchase these and I would be reimbursed for the amount, so I opened up an RMA, returned the bad modules with receipts from both purchases only to told they would make out a check for the original memory and NOT THESE! These were slightly more and the C.R. was told but she made it a Customer Courtesy for the inconvenience this caused! I did contact Corsair but they were firm on just reimbursement of the original purchase/memory. My next build will be using Kingston, I just have no confidence in the Customer Relations in the even things go bad at this point.

I only gave this a four because one of the two I ordered was bad and I had to send both of them back to Corsair for replacement. I am being told that two packs are paired together so even though one of them worked I had to send them both back for replacement.I have read over and over again that when adding RAM buy the exact model of ram that is already in the system or replace all the chips with the same new models. I already have these exact two in my system and since I went from 32 bit XP to 64 Bit Windows 7 I decided to up my RAM only because I could.Windows 7 is so much faster than XP it is truly amazing!I did NOT by the RAM to make Windows 7 faster I bought the RAM because I could and because I am staring to do a lot more 3D CAD and Animation and that takes a lot of horsepower.BUY THIS RAM IT IS WORTH THE PRICE!

I installed these in my Dell XPS 720 tower. It maxes out at 8GB of RAM running Windows 7. The motherboard cannot take anymore, since it was developed for DDR2 capabilities mainly. I installed the new modules, the BIOS picked up the new DIMMS, continued the boot up process and once in Windows 7, I saw all 8Gigs of RAM with no issues. Very happy with the modules, also they look cool with the heatsink casing.

Used in Dell XPS 210 compact desktop as a max upgrade option. I made so many changes at once (incl SSD, videocard with integrated cooling fan) that I can't attribute the improved performance to the Corsair card alone but the whole systems runs SO MUCH faster, cooler and quieter that I don't know how I ever tolerated it before.

these are a perfect match to my existing modules, so computer and user are both happy. and i wish amazon wouldn't set a minimum on the number of words used when rating a product. amazon, are you listening?!

Great boost for my aging PC.Ordered two more 2x2`s to max out my old tower.No worry about overheating. And make no mistake, RAM can get hot.

I recently upgraded my 5 year old Compaq Presario for Windows 7 x64. I replaced the original 2 gig + 1 gig with this 2x2 4 gig kit. This upgrade alone nearly doubled my Windows Experience Index score... And it took exactly 5 minutes to upgrade.Pros: Fast, easy, works in proprietary Compaq.Cons: A bit expensive.

So they worked right out of the box at the speeds they should. I guess for most people that's great. But that's where the performance ended for me. I have overclocked my PC's for years and have always used corsair memory. Anytime I have tried any other high end brand of memory they either failed within a month or failed instantly. I also love corsair for over clocking they always leave a lot of overhead play room to push up timings and voltages. ANY kind of increase with timings or voltages with these and my PC beeped and wouldn't boot.So from me they only get 3 stars (it's ok). Corsair normally gets 5 stars from me for all their products.

Please note: this is a review of the Corsair XMS2 6400 _kit_ of 4-GB (2+2) DDR2 DIMM modules with product code TWIN2X4096-6400C5DHX bought directly from AMAZON UK, not from any marketplace reseller (there are lots of fake/defective/used RAM banks out there, so you should always be careful what you buy and who you buy from, IMHO...)I bought these to breathe some more life into my old Asus Rampage Formula motherboard, which I stil use under XP and Vista. If you intend to buy this kit, as I did, please always check compatibility with your specific motherboard on the very detailed Corsair RAM configurator web pages, and make sure that your specific motherboard is listed as compatible.By the way, you should also always check that the original Corsair product code actually appears in the description of the product you are buying, since there are very similar products which might not be compatible. (You should always check for number of pins and number of chips on the RAM, by the way, and for the original specs of your specific motherboard, in order to be sure that it actually supports the installation of 2+2 GB RAM banks, as opposed to 1+2 GB configurations, for instance).This is a matched kit of indentical DIMMs, made to ensure proper dual channel configurations, on motherboards which support this feature, and I used it to replace my corresponding kit of 1-1 GB XMS2 DIMMs, which I bought 5 years ago.The banks I received were brand new, genuine and in perfect conditions (they arrived in a large protective Corsair blister, inside Amazon's usual packaging); they were accepted and recognized immediately in my Asus Rampage Formula (which can be very temperamental, as regards RAM banks...), and I had no problem in using 4 GB under XP or 32-bit Vista, even if only slightly more than 3 GB (3.3 in my case) are actually available (you cannot use all 4 GB of RAM under a 32-bit OS, in case you did not know, due to the 32-bit memory addressing limitation).The rest of the RAM should not be actually used, since it overlaps the memory addresses reserved by the memory banks used by the various devices installed on the motherboard, such as graphic card, audio card, etc.The DIMMs work perfectly, with no glitches or blue screens, so far; nevertheless, with 4 GB of RAM instead of 2 under 32-bit XP or Vista, honestly I did not notice any speed improvement in OS startup or in average daily operations such as Web browsing, text editing, etc., but I got some noticeable improvement only when using memory-hungry applications, such as those for photo editing, voice recognition, etc.So, you should not expect a more reactive or faster _OS_, unless you are upgrading from 1 GB or less, but some faster or more performing applications, depending on how much memory they can actually use... If you want to improve the OS speed, you might want to upgrade the HDD, instead...By the way, by using 4 GB of RAM under a 32-bit OS, there is always the remote chance that some badly written audio or video device driver might unexpectedly crash the system under some particular circumstances, since the memory addresses used by memory banks in these devices (especially the video and audio cards) might conflict with the overlapping RAM addresses that exceed the 3-GB intrinsic limitation of 32-bit OS.Finally, in case you did not know these specific DIMMs, please note that they are very _high_ (more than 5 cm in height, including the contacts), due to the very large, typical "custom" heat spreaders on top of them, which is maybe their most recognizable feature, which helps in dissipating their heat. So, before buying and/or installing them, you should ensure that no power or data cables will get in the way or jam betweeen the metal fins on top of the banks.All in all, even if these might not be the fastest or cheapest DIMMs of this kind around, I can strongly recommend them for their high reliability (I never had a single problem with them in 5 years) and very good price/performance ratio.

I bought these to upgrade and to cure a problem with windowsunfortunately the problem still excists but I am sure that these are not at fault

I got these as an upgrade for my ageing machine. My current RAM was CL4, and these work fine, with the motherboard slowing my CL4 down to match the slower CL5. That said, a little tweak in the BIOS and these CL5's are happily running faster, so there is clearly some overclocking potential in the RAM I received.

Bought these to replace the faulty pair in my unit. No problems

Excellent, as expected.