Fill all RAM slots or not?

CmdrJeffSinclair

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Aug 29, 2014
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Would filling all 8 RAM slots with 4GB DIMMs be better than filling only 4 slots on the ASUS X99 Deluxe?

I've read mixed reports about performance regarding this.

Some say a few percent memory increases occurs when all slots are filled while others say that filling all the slots just makes the memory controller have a harder time.

So which is true?

MY RIG:
CPU: Intel i7-5960X overclocked to 4.5GHz
COOLING: Swiftech H20-320 Elite 3x120mm fans@86 CFM w/ 360mm Radiator 12FPI
MOBO: ASUS X99 Deluxe w/ Thunderbolt II
RAM: 16GB G.Skill Ripjaws DDR4 3200MHz (4x4GB, 4 slots empty)
--RAM Timings tightened from 16-16-16-36@1.35v to 13-13-13-33@1.4v
GPUs: 2x 4GB Gigabyte G1 Gaming NVIDIA GTX 980s SLI both PCIe 3.0 x16 lanes each
STORAGE #1: 1TB Samsung 850 Pro SSD's SATA III (linked to 4GB RAM 1300MB/s read/write)
STORAGE #2: 2TB Seagate Barracuda SATA III 7200RPM (backup)
STORAGE #3: 750GB Seagate Momentus XT Hybrid SATA III 7200RPM (extra backup)
PSU: Corsair AX1500i
CASE: Corsair 900D
DISPLAY: Optoma HD141X 1080p Full 3D Gaming/Home Theater Projector 3200 Lumens
 
Solution
No you won't lose performance with 8x4GB vs 4x4GB - you gain as you would have 32GB (8x4=32) vs 16GB (4x4GB) - but if going 32GB the 4x8GB is better than 8x4GB

2x8GB will work - in dual channel, but don't count on just adding another 2 sticks here or 4 sticks there, mixing DRAM can be and often is problematic, even with identical sets of the same model. It's not like many seem to think that you can just throw any old sticks in together, it's a crapshoot, they might play they might not. That's why DRAM is offered in such a wide variety of sets, the sticks in a given package are tested to work together, which is also why a 4 stick package often runs more than two sets of 2 stick packages of the same model - the additioanl teting to...


Minor server use for LAN hosting on games. I pay for a Ethernet through Comcast and I have enough bandwidth to host games on PC. I also game with my desktop at the same time WHILE hosting (not all games allow me to do this since some require special software to run in a virtual OS). I would probably be OK with my 5960X and 16GB DDR4 but I want to eek out all the performance I can since this might be murder later on if I gather more friends to all play together. Next gen games are going to start allowing for 16 and more players per match, so that's a butt-load of CPU usage while I game with them.

People pay hundreds of dollars for that extra 2-3% of performance and I certainly paid a lot already so it's worth it to me. So my question is a good one in my case. The RAM probably won't be used much past 16GB but it's a very interesting question.

I will update my original post now since I forgot to include my system information
 


ASUS Deluxe, max RAM is 64GB

So based on what you said, I would get the best performance by either filling 4 of the 8 slots or filling all 8 slots to max RAM?

1) So if I shoot for 16GB RAM, I'd want 4x 4GB and leave the last 4 slots open
2) If I want 32GB, I'd want 4x 8GB, again leaving the last 4 slots open for better performance
3) And only fill all 8 slots if I go for max RAM 64GB, as in 8x 8GB (64GB)? Yes? No? Maybe so?

Right?

So this means that unless I need more than 16GB RAM, I'd lose performance if I chose 8x 4GB over 4x 4GB?

QUESTION: What if for future purposes I chose 2x 8GB? That way if I wanted to hit the 64GB mark one day I would not have to throw out smaller sized RAM sticks. Is it ok to fill half of the slots or would I be forced to do things in 4's since there are 4 slots, and again 4s for the next 4 slots? All would have to be the same size as well, right?
 
No you won't lose performance with 8x4GB vs 4x4GB - you gain as you would have 32GB (8x4=32) vs 16GB (4x4GB) - but if going 32GB the 4x8GB is better than 8x4GB

2x8GB will work - in dual channel, but don't count on just adding another 2 sticks here or 4 sticks there, mixing DRAM can be and often is problematic, even with identical sets of the same model. It's not like many seem to think that you can just throw any old sticks in together, it's a crapshoot, they might play they might not. That's why DRAM is offered in such a wide variety of sets, the sticks in a given package are tested to work together, which is also why a 4 stick package often runs more than two sets of 2 stick packages of the same model - the additioanl teting to group 4 sticks that play together takes longer than finding two sticks
 
Solution


awesome response. I will wait for G.Skill to make 8GB DIMMs at 3200MHz bandwidth to upgrade to 32GB (8GB x4, that way if I need even more later on I wont need to buy 8 new sticks of RAM)!