Dual channel mode for HP - Pavilion HPE - h8-1234

[dondean]

Hi everyone.

Just purchased (online) an HP - Pavilion HPE - h8-1234 that comes with 10G RAM.

A sales person said it has 4 DIMM slots and one is open, so I suspect that it has 2 x 4G and 1 x 2G DIMMS.

I'd like to add 6-8 Gig more RAM, but want to make sure it is running in Dual channel mode after I do the upgrade.

Can I add one 8G DIMM in the open slot, or will I have to install 2 x 4G DIMMS and remove the 1 x 2G DIMM?

Or maybe I should consider adding 2 x 8G DIMMs and remove the 1 x 2G DIMM.

I do a lot of Photoshop work and my old computer would barely run with 4G RAM.

Thanks

[lasvegaswireman]

Here are the specs for your HP Pavilion HPE h8-1234 Desktop Computer. Regardless of how much memory you decide to install, you need the install matching pairs of memory for dual channel mode to work. You will have to remove the 2GB DIMM and install two matching DIMM's for it to work as you want.

[banhien]

Hi,

Based on this the motherboard can support up to 32GB of RAM. Normally for dual channel we have to use 2 banks same RAM specs and same manufacturer. As it only supports 1GB, 2GB, 4GB & 8GB each bank you can work out the number(s) to get the full benefit.

Your existing can be 4GB x 2 + 1GB x 2. If 4GB x 2 + 2GB x 1 then the open slot can be 2Gb. RAM is very cheap now, just add another set 4GB x 2 and you have 16GB.

Regards.

[Big_Dave]

Hi dondean,

You can use CPU-Z to verify memory channel operation.

[dondean]

Thanks Frank

So if I remove the 2GB DIMM and install a pair of 4Gig DIMMS, there's no question about where they go because all DIMMS will have 4Gig.

If instead, I install a pair of 8Gig DIMMS. Will they still go in the same open slots.  I don't have the PC yet, so don't know where the existing DIMMS are. According to the motherboard layout, starting nearest the CPU, there are 4 slots: 1 black, 1 blue, 1 black, and 1 blue slot (say 1,2,3,4).

Should the 8Gig DIMMS go into 1,2 or 3,4 or 1,3 or 2,4?  This is all new stuff for me.

Thanks

Don

[dondean]

Thanks BH.

Just curious. With the factory installed RAM, the 2Gig DIMM is not paired. Does that negate the PC from running in dual channel mode or would the pair of 4Gig DIMMS still run that way if they are installed in the correct slots?

When you say:

---

banhien wrote: Normally for dual channel we have to use 2 banks same RAM specs and same manufacturer.

---

Are you talking about the same "color" slots.

Thanks

Don

[dondean]

Thanks Big Dave,

That looks like a nifty tool. I'll check it out.

Don

[banhien]

Hi,

The following topic/video may help, including color coded RAM slots:

   http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=bph03886

Good luck.

[lasvegaswireman · Accepted solution]

Please read this very helpful article entitled "Everything You Need to Know About Dual, Triple, and Quad Channel Memory Architectures" The link provided starts you on page 5 of the article... this is where the nuts and bolts of correctly installing the memory is explained. Page 6 is a continuation of the dual channel topic.  Basically it states, on most Intel and newer AMD motherboards... place the matching pairs of memory into the same colored sockets (XMM1 and XMM3, XMM2 and XMM4 on these systems). On older AMD motherboards... place the matching pairs of memory into the same colored sockets (XMM1 and XMM2, XMM3 and XMM4 on these systems). There are some rare exceptions to this rule.

So, on your system it should be a matching pair in 1 & 3 and another matching pair in 2 & 4... If you purchase a matching pair of 4GB DIMMs, install them in either 1/3 or 2/4 and place the original pair of 4GB DIMMs in the remaining slots (make sure the original DIMMs are a matched pair).  If you purchase a matching pair of 8GB DIMMs, install them in 1/3 and place the original pair of 4GB DIMMs in the remaining slots (make sure the original DIMMs are a matched pair).

Note: If the original 4GB pair isn't a matched set, the system will work in single channel mode. If you mix an original 4GB and a new 4GB, the system will work in single channel mode.

[Big_Dave]

Hi,

The points to keep in mind are:

1. Keep the matching DIMMs in the same color sockets
2. Try to use all DIMMS from the same manufacturer
3. Use DIMMS with the same specifications:  speed and CAS timings
4. Keep all the DIMM slots filled. Some PCs will run "unbalanced" if there is an empty slot.
5. Some PCs need the largest DIMMS in bank 0 of each channel. 8/8 then 4/4 or 8/8 and 2/2 or 4/4 and 2/2 etc.

Frankly, I am hoping that the salesman misspoke about the PC being equipped with 10 GB has one slot open. It would be better for memory interleaving and improved performance to have all slots populated.