Z400 Memory - 6 slots

[BrianA012]

Hello...again

I purchased a HP Z400 Workstation Xeon Quad-Core W3565 3.2GHz 8GB 1TB DVDRW Windows 7 Pro

as it was listed as a supported pc from Avid to record with Pro Tools. For those paying attention, I've been asking a good amount of questions lately here on the board The site so far has been extremely helpful and I'm glad I went HP for this reason indeed

I have 8GB of RAM, as it was suggested, but now I see with all involved for my projects, 8GB is the minimum amount need

I see that there was a possiblity for 24GB of RAM, and I decided I wanted to go at least to 16GB

I popped open teh Z400 to take a look under the hood. 

I found in slots 1 through 4 that each had a stick of 2GBs for make the toal of 8GB. What I was hoping to find was only slots 1 & 2 with 4GB, so I could add for now 2x4GB to slots 3 & 4 and then eventually 2x4GB in 5 and 6

My question is this, could I still add 2X4GBs to the set up, to add 8GBs to the 8GB I already have for a total of 16GBs?

Could I add 2X4GBS into slots 5 & 6? Or would I add 2X4GB to slots 1 & 2 and move for 4X2GBs into slots 3 4 5 & 6?

Or is mixing 2X4GBs and 4X2GBs not possible/not advised?

Any help would be seriously appricated, I'm knee deep in hardware nuts and bolts right not preparing the recording studio

[Dan_WGBU · Accepted solution]

Some mixing of 2GB and 4GB DIMMs will work, but not all configurations are validated by HP.  You might be able to add qty. 2 4GB DIMMs and get 16 GB total, but that will not give highest memory performance. 

The Z400 has 3 memory channels.  The CPU can access all 3 channels at the same time, which gives the most memory bandwidth and performance.  (OK, this is a big simplification).  For all 3 channels to work together, they must have the same type of memory in each channel. 

A suggestion is this: 

Get qty. 3 4GB DIMMs, and put them in the black connectors.

Put 3 of the 2GB DIMMs in the white connectors. 

Now there is 18GB of memory, with higher performance, and you used some of the memory you already have.  

Make sure the 4GB DIMMs are similar to the 2GB DIMMs already in the system, that is, they are ECC, unbuffered, and have the same technology  chips (x4 or x8). 

[BrianA012]

so 4x2GB with 2X4GB = 16GB is no good but 3x4gb all in black slots and 3x2GB in white slots = 18GB is good, yeah?

I mean I was fingers crossed for 4x2GB and 2x4GB was gonna work, but this is all about performance, so I'll go for 3x4GB and 3x2GB if you think it's going to lead to the best performance is this current senario

I mean sometime soon, I'm assuming mid-2014 (so much hardware this and that's going down right now for the home studio) I'll end up going full blown 6x4GB for a total 24GB, but for now I'll go for your option of 3x4GB black & 3x2GB white for sure

Many thanks, I guess I'll go ahead and hit resolved

[BrianA012]

Actaully, interseting question

because it was all 2GB sticks, and had 3 in black slots and 1 in the white slots, would that have effected the performance of the machine, have a 3 to 1 set up, 3 in black and 1 in white? Of was that cool because they completely filled in the black 1st?

[Dan_WGBU]

Let me explain my comments more. 

4x2GB with 2X4GB = 16GB is "good", it will work.  Also, 4x2GB, with 3 in the black slots and 1 in the white slot, will also work.  More memory capacity usually gives higher performance for most applications anyway. 

But 3x4gb all in black slots and 3x2GB in white slots is "best".  If one is buying new memory, putting identical memory in each of the 3 channels (a channel is a pair of black and white connectors) gives maximum memory performance.  This is how the Z400 CPU is designed. 

it is hard to say what gives users more performance - more memory, or following memory installation guidelines.  Performance depends on the programs being used, so  I was just giving recommendations based on what the hardware can do, because you are using this Z400 with an application that can use high performance. 

[BrianA012]

works best sounds good to me, many thanks for your help indeed!!

[Dan_WGBU]

Dan_in_WGBU wrote:

Make sure the 4GB DIMMs are similar to the 2GB DIMMs already in the system, that is, they are ECC, unbuffered, and have the same technology  chips (x4 or x8). 

I was told that, for the Z400, the memory chip technology (x4 or x8) does not matter.  They can be mixed in the same system, as long as they match the other memory requirements (DDR3 1333 or higher, ECC, unbuffered).

[K19]

Good evening. My HP Z400 6 slot Xeon W3680 runs fast and stable, but reading your post(s) I'm thinking to upgrade Ram.

Now I have all 6 slots filled with 2GB ECC modules (12Gb) so upgrading with three 4Gb modules in the black slots and leaving the white ones with 2Gb (18Gb total) will give some overall bump (e.g. a more responsive system) or it will be only useful when opening large files? Thank you for reading this post.

Rob