OptiPlex 745 Ram sticks

Question

I had 4 memory sticks then my computer stopped reaching the desktop. I reseated and nothing. Then I started removing ram. It appears 3 sticks work fine but the 4th doesn't work. My question, if I want to replace that memory stick, why do online memory vendors suggest buying in 2's. for this computer. I only need 1 stick. Does this computer have a memory requirement that insists on 2 sticks? Will I have to remove a functioning ram stick just to make room for a new stick?

mrpetedell · Accepted Answer

SpeedStep is absolutely right and that's why memory vendors tell you to buy RAM in pairs for an Optiplex 745.However, in your case you could just buy 1 'stick' IF YOU BUY THE EXACT SAME DIMM (stick) AS THE ONE THAT DIED.It is also sometimes possible to mix 2 RAM DIMMs ('sticks') that are almost the same, but just slightly different, in the same channel (white or black slots) and get away with it. I do not recommend that for you and it is something that I generally stay away.So, here are your options:1 - stay with your 3 working DIMMs = you have less RAM2 - get the exact same DIMM as the one that died = same RAM as before3 - get a pair of DIMMs either new or used = maybe change, maybe notYou haven't told us if you have a 745 minitower, desktop or SFF. You can't have a USFF because that only has 2 DIMM slots. You also haven't told us what the DIMM size is that you have in your machine. I guess it might be 2 GB, 1 GB or maybe 512 MB.Your machine is a bit old and you might want to consider upgrading to a more recent model. It doesn't have to be a new machine. You could get a used Optiplex 790 or whatever ... just something more recent.If you are going to stay with the 745 and you had a 1 GB DIMM die on you then you might possibly upgrade that channel to 2 GB DIMMs. That means that you buy 2 DIMMs and you would have an extra (useless) 1 GB DIMM on you hands after the upgrade. I'm hoping that you don't have 512 MB DIMMs.You have options ...Option 1 of staying with 3 DIMMs may not be such a good one. Typically, a dual channel motherboard like yours will only be happy with an odd number of DIMMs if there is just 1 DIMM plugged into the board. 3 DIMMs in that kinda mobo can easily stop the mobo from booting. If yours boots with 3 then it is at least partially OK with that config and might be fully OK with it. I guess that it might be possible for it to boot and yet still ignore the 3rd DIMM. You would have to check with OS.Option 2 of replacing the dead DIMM with another of the [exact] same is pretty good. You can very likely get another used DIMM on either eBay or Amazon. Both have good guarantees. If you receive a non-working DIMM (rather unlikely) you either get your money back or you get another DIMM, but you have to complain to the seller/eBay/Amazon in order to get the replacement DIMM. It may or may not be difficult to find a brand new exact replacement for your dead DIMM. It depends on the DIMM.Option 3 is pretty much like option 2, except that you might be able to upgrade to 2 GB DIMMs if that is not what you have now. Both new and used DIMMs are options here.Your 745 takes 1 GB and 2 GB DDR2 DIMMs. Those are pretty cheap these days if you buy them used. In my experience used RAM from eBay/Amazon is just as good as new, but YMMV. Some folks just feel better about buying new parts and getting a 1 yr/90 day/whatever guarantee. Choose wisely, grasshopper.

speedstep · Answer

The ram is dual channel.   It needs to be in pairs. Thats why there are black ejector ears and white ones because its 2 sets of pairs.

OptiPlex 745 Ram sticks

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