XPS 8940, memory upgrade of 2x8GB

@jjmax0789 The only negative to operating at 2666 MHz is slightly lower performance since the maximum for the XPS 8940 is 2933 MHz with your CPU. I don't think the performance hit would be noticeable with everyday applications, only if run benchmarks.

The only suggestion I would have made before you brought the 4x8GB is that you should have purchased a 1x16GB Crucial memory module to use with the one you already had. 

I note Dell specs the memory 2666 / 2933.. what does that mean? Is the memory really running at 2933? or 2666? or is it like the processor - it runs faster depending on the temperature? If I install new memory, it's hard to find 2933 spec, and most go from 2666 to 3000. I'm just confused on this spec. 

Thanks

Scott

@Colorado_scott First, Dell installs memory that is specified at 3200 MHz. According to the XPS 8940 specs, the installed memory runs at 2666 MHz if the CPU is an i3/i5 and 2933 Mhz if the CPU is an i7/i9. The speed the memory runs at only depends upon the CPU that is installed; its speed does not depend upon temperature. You are correct, it is hard to find 2933 MHz memory but that is not what Dell uses.

Thanks, this helps me understand better.. appreciate your time letting me know.

sc

I'm thinking about upgrading and your memory usage is very interesting @fireberd 

I have 14 Chrome windows open with multiple tabs in each, the Netflix App and Firefox with 5 windows open (multiple tabs)

I have 64GB of RAM but I'm using 30.6GB (48%) of RAM

That seems like alot of memory usage for basically a bunch of browser windows but maybe it's not. 

@jmgbooks  - Chrome is a known memory hog, especially if you have a lot of extensions installed/active.

The clock speed of the memory isn't all that is important for performance.  Your Crucial Ballistix memory has a CAS latency of 16 cycles compared to 21 cycles for the original memory supplied with the Dell XPS 8940.  Even at 2600 MHz, your Crucial Ballistix memory has an access time of 12.3 nS compared to 14.3 nS for the memory supplied by Dell.

Note:  This was written from my Dell XPS 8900, which has 16 MB of 2133 MHz CAS 15 memory, giving an access time of 14.0 nS, so effectively faster than my XPS 8940.

Ok,  so this didn't work great for me.  I had 2x8GB in my xps 8940 with a i7-10700.  I purchased 2x8GB of ram from Dell and installed it.  The RAM speed went from 2933 MHz down to 2400 MHz.  Interesting thing is when I put only the new Ram it worked and ran at 2933 MHz.  Oddly enough any combination of the new and old RAM would work and operate at 2933 MHz but as soon as I put in 4 sticks of RAM (in any order) the system would drop down to 2400MHz.  My experience is that the XPS 8940 i7 does not support 4x8GB of RAM at full speed even if you buy and use DELL branded memory.  

2 sticks works fine (any two sticks of Ram)

PC Mark for 2 sticks is

4 sticks the Speed slows down. Now the Latency timing improves so performance doesn't drop too much but it does drop.  

@RaymondGarcia We can't see your pictures until they are approved by the moderator of this forum, but If you look at the Setup and /Specifications, there are only two 32 GB configurations supported, 1 x 32 GB and 2 X 16 GB. At least your configuration works even though it is at a lower speed. If you intend to stay with this configuration I would run Memtest86 to make sure there are no other issues.

@bigfraggle007 You have to pay close attention to the memory configurations. For 16 GB of memory, Dell offers two configurations, 1 x 16 GB and 2 x 8 GB. The Dell XPS sales site says 1 x 16 GB is 'Included in price' and 2 x 8 GB is $0.00. For 32 GB of memory, the XPS 8940 Setup and Specifications also lists two configurations, 1 x 32 GB and 2 x 16 GB. 

@RoHe

Why extra $$$? The 16GB bars are quite cheap. And they only have 3000 MHz. So the loss is not really big ...

@Vic384

As I said, I want to buy 2x 16GB because a total of 4x 8GB is not possible according to Dell.

I just wanted to know if 2x 16GB with 3000 MHz will work. In the end, I don't care if it's 3000 or 2933. But it should be 2933.

I'm considering buying an 8940 with an i9-10900k and a RTX 3060 Ti. The built-in 2x 8GB RAM bother me too and I will probably buy 2x 16GB, since 4x 8GB can apparently cause problems.

Since the 8940 supports a maximum of 2933 MHz, I plan to buy 2x Crucial Ballistix 16GB 3000 MHz (BL2K16G30C15U4B). More MHz wouldn't make sense, would it?

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@bigfraggle007 wrote:

I'm considering buying an 8940 with an i9-10900k and a RTX 3060 Ti. The built-in 2x 8GB RAM bother me too and I will probably buy 2x 16GB, since 4x 8GB can apparently cause problems.

Since the 8940 supports a maximum of 2933 MHz, I plan to buy 2x Crucial Ballistix 16GB 3000 MHz (BL2K16G30C15U4B). More MHz wouldn't make sense, would it?

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It's still going to clock down to 2933 MHz, so is Ballistix worth the extra $$$?

Thanks!