Supported memory configuration for Dell Optiplex 745?

Depends on the CASE Size.

DDR2 PC2-6400 • CL=6 • Unbuffered • NON-ECC • DDR2-800 • 1.8V • 256Meg x 64 •

https://www.crucial.com/usa/en/optiplex-745-series-%28desktop-mini-tower-and-small-form-factor%29/CT757662

2 GIGS is max dimm size  and 4 or 8 gigs is max ram depending on how many ram slots your machine has.

Hi,

Its a Mini Tower and it has 4 memory slots.  So it has 2x 1GB RAM sticks right now and I would like to populate the 3rd and 4th slots with 2GB sticks.  But I will try adding one first, so is it supported to have 2x 1GB and 1x 2GB sticks configuration?  The existing memories are DDR2 PC-5300 by the way so I guess I have to get the same kind.

Thank You!

Logbi

Optiplex 745 Publications

Welcome to the Dell Community  @Logbi 

Memory
Type 533, 667, or 800 MHz DDR2 SDRAM

NOTE: 2-GB 800-MHz memory modules are not supported.

Memory connectors 4

Memory modules supported 256-MB, 512-MB, 1-GB, or 2-GB non-ECC

Minimum memory dual-channel: 512 MB

single-channel: 256 MB

Maximum memory At 533 or 667 MHz: 8 GB

At 800 MHz: 4 GB

Dell™ OptiPlex™ 745 User's Guide:

Mini Tower Computer Specifications:

https://downloads.dell.com/manuals/all-products/esuprt_desktop/esuprt_optiplex_desktop/optiplex-745_user%27s%20guide_en-us.pdf

Best regards,

U2

Hi donm4599x,

Thank you so much for you help!  This is exactly what Im trying to figure.  

" NOTE: 2-GB 800-MHz memory modules are not supported "

i purchased 2gb 800mhz memory by using a memory configurator, and later found this note as i was searching for the size of the hdd bay ( is it 3.5"  ?)

1.  is there a bios setting so that i can manually set the timing to 667, or will spd switch it automatically to 800

2.  using mixed memory modules drops the speed down to the lowest specification, so i can check to see if 667 modules are installed, and only populate one bank for 1+2+1+2 gb = 6 gb (instead of desired 8 gb)

is there a bios setting for timing ?

i don't have the desktop in front of me, so i won't be able to find out for another 2 weeks

should i go ahead and exchange the memory modules now instead of experimenting

note: they say to not post questions in the answer section, but it's about the same optiplex 745, so i am hoping someone here may know the answer opposed to posting it on the forum

RAM speed cannot be changed in BIOS.

thank you for that.  i'm left wondering how do you know.  do you own an optiplex 745 ?  is memory timing not configurable (vs cpu timing) ?  can you give me some insight into your answer

1.  Experience with BIOS.  Optiplex's 755, 790, 7010.

2.  Only one thing changes RAM speed.  If you put 2 sticks 800MHz in your 745, then a stick with 667MHz, the system will operate all the RAM at 667MHz.

3.  Over 2 years experience on this forum.

4.  Over 100 total manuals, tech guides, spec sheets, & etc. downloaded for various Dell's.  All of those things can be Googled.  I download those from Dell only.  So I pay attention to Google's links or download from Dell site.

There isn't a Tech Guide for the 745 that I could find.  Below is a screengrab of what I do have on it:

Also:  https://www.dell.com/support/home/en-us/product-support/product/optiplex-745/docs 

Hi @hamoo,

I didn't quite answer your first quite as completely as I would like.

Dell said 8GB (total) 800 MHz RAM not supported.  They didn't say "not working."

I'd try the RAM you bought.  If it works, it may run at a slower speed.  The slower speed may show that way in BIOS & Windows.  At worst, it won't boot.  It won't break your PC.  If it doesn't work, then trade it.

From the Tech Specs.:

From the User's Guide:

Is there the possibility that it will read only 4GB of the 800MHz RAM?  May be.

I also posted the above screengrabs because U2CAMEB4ME initially confused me a bit with the statement of "2-GB 800-MHz memory modules are not supported."

if i could give you two kudos, i would

i'm going to go ahead and try it.  nothing to lose.  i'm getting conflicting answers (from here and from memory4less).  dell never comes out and says why it won't work.  maybe it's because the 2 gb sticks might need to run at a higher voltage (speculation).  i checked the voltage on these, and it matched up to the motherboard voltage, 1.8 v

if it doesn't work, i'll probably end up putting it in another pc

whatever happens, i'll post an update.  won't find out for two weeks; i'm not onsite, and it's far away

BIOS layout seems to be unpublished.  I have to see it in any Tech Guide or manual for Optiplex's, let alone the other manuals I have.  I can't speak for all of Dell's PC and server manuals though as I certainly can't answer questions on all of them.