Why is my new RAM running as DDR-1330 instead of 1600?

[dc2000]

I just purchased new Dell XPS 8700 tower:

http://www.dell.com/support/Manuals/us/en/19/product/xps-8700

It originally came with 8GB of RAM, which I decided to upgrade to the maximum supported 32GB from here:

http://www.amazon.com/gp/product/B0068ZWZY0/ref=oh_details_o04_s00_i00?ie=UTF8&psc=1

So I got this 32GB ram that supports DDR3-1600. I then ran it through the Memtest86+ and got this result:

RAM: 665 MHz (DDR3-1330)

Here's the screenshot:

http://en.community.dell.com/cfs-file.ashx/__key/communityserver-discussions-components-files/3514/_5F00_low_5F00_new_5F00_ram_5F00_32gb.jpg

I then ran the original RAM through Memtest86+ and got this:

RAM: 798 MHz (DDR3-1596)

Here's the screenshot for that:

http://en.community.dell.com/resized-image.ashx/__size/550x0/__key/communityserver-discussions-components-files/3514/_5F00_low_5F00_old_5F00_ram_5F00_8gb.jpg

So my question is how come my new RAM runs slower? Is there a setting or a jumper I need to adjust?

 

[smorizio]

in the bios of yur dell see under dram speed it has a setting called xmp profile. the newer ram is set to run at 1600 under intel xmp profile.

 

[dc2000]

in the bios of yur dell see under dram speed it has a setting called xmp profile. the newer ram is set to run at 1600 under intel xmp profile.

Thanks. I just checked, and there's no setting under DRAM that I can change. In the main screen it just simply shows what RAM is installed.

 

[smorizio]

download the manule for your pc look in the bios setting for ram speeds. you have to change your ram speed.

 

[dc2000]

download the manule for your pc look in the bios setting for ram speeds. you have to change your ram speed.

I checked the BIOS itself. It doesn't have an option to change RAM speed. Take a look for yourself:

here

Sorry, the automatic link parsing on this site does not work. The link above has an apostrophe or ' between Owner and s.

 

[saint19]

What happen if you install the old RAM and add one set of the new one?

 

[dc2000]

Just want to update this thread in case someone else has to go through this. Buying RAM for Dell towers, it turns out, is not as straightforward as it seems. The reason is that the system board comes with a very cheap BIOS/UEFI that does not support much variation for different RAM clock speeds. For instance, I first bought expensive Corsair RAM that by itself supported 1660 MHz speeds, but in despite of that my XPS 8700 tower ran it only @ 1330 MHz. I did more research and found out that the RAM latency was what was causing the drop in speed. For some reason the system board on this XPS 8700 only supported CL-11 RAM to run at higher speeds.

So the bottom line, I ended up buying x4 of the following 8 GB sticks:
"Kingston ValueRAM 8 GB 1600MHz DDR3 (PC3-12800) Non-ECC CL11 DIMM Motherboard Memory (KVR16N11/8)"

Amazon had a better deal for them:
http://www.amazon.com/gp/product/B0089JIDLC/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

They worked fine in my XPS 8700 system, and ran at DDR3-1660. I tested them through 16 passes with Memtest 86, which they passed just fine. Here's the screenshot for whoever is interested in detailed specks:
http://i150.photobucket.com/albums/s99/dc2000_bucket/Kingston8GB-x4_zpsbc0908ba.jpg