Memory increase question

[TheJTrain]

Current state:
Gigabyte GA-Z77X-UD3H
Core i5 3570K
2x4GB Patriot Viper DDR3 1866 (PC3-15000)
Samsung 850 EVO SSD
eVGA GTX 670
Not running in XMP mode (but I could, given the above), so the bus is only @ 1600

I'd like to go to 16GB, but the simplest solution (another 2x4GB of exactly the same mfr/model RAM) doesn't look like it's in the cards, based on availability.

So, #1: is there any appreciable difference between 4x4GB and 2x8GB, assuming whatever I don't mind whatever net expense difference there may be?

#2, if 4x4GB is the way to go, how important is it to match the new pair to the existing pair, speed-wise? If I'm only running the bus @ 1600, would there be any impact to buying a DDR3 1600 (PC3-12800) pair to go with the pair listed above? The speeds won't match but they'd both be fast enough for the non-XMP bus speed I'm running.

Thoughts?

Thanks!
JT

 

[LTC8K6]

http://www.amazon.com/Patriot-1866MHz-Desktop-Heatsink-PV38G186C9KRD/dp/B0098WZV1Y

 

[TheJTrain]

Ah - guess I should have looked closer! I searched by the model ID and found it had been discontinued. Here's the model I'm running, different branding but the stats look identical except for one digit off on one of the timings.

Thanks!

Any thoughts on question #1? I'd be willing to go 2x8GB instead if there's a reason to do so other than the possibility of eventually going 4x8GB, which I doubt I'll do on this platform.

 

[dave_the_nerd]

Unless you're overclocking, the new RAM doesn't have to be exactly the same. It just has to be close. The motherboard should figure out the rest, and clock the RAM to the lowest common speed.

There is a small chance your motherboard will decide to drop speed back because all four slots are populated. (I've seen this happen.) If it does happen, don't worry about it.

 

[TheJTrain]

There is a small chance your motherboard will decide to drop speed back because all four slots are populated. (I've seen this happen.) If it does happen, don't worry about it.

I think that's what I had some vague memory of hearing about, but second-guessed myself in considering the opposite, some kind of bottlenecking that might happen with fewer, larger modules that wouldn't be present with more, smaller modules.

When you say "drop speed back" do you mean to a speed that matches the slowest-speed module, or a speed slower than that?

 

[dave_the_nerd]

I think that's what I had some vague memory of hearing about, but second-guessed myself in considering the opposite, some kind of bottlenecking that might happen with fewer, larger modules that wouldn't be present with more, smaller modules.

When you say "drop speed back" do you mean to a speed that matches the slowest-speed module, or a speed slower than that?

Slower. Now my memory is returning to me... lessee...

It was an nvidia 750i motherboard, ASUS I think. Socket 775. I had four sticks of DDR2-800, and any two sticks in any two slots would run at 800MHz just fine, but if I filled all four slots, it would default to DDR2-667. The behavior was actually documented in the manual, but I wasn't expecting it.

If I overclocked the RAM, it would crash anywhere north of 700MHz.

Dunno how common/necessary that is anymore, things change. OTOH, overclockers still have stability problems with 4 slots populated vs. 2, so it's not like there's no difference at all.

 

[Ketchup]

Running 4 sticks may clock down if running spd. This is normal (nore distance to travel). Is it an appreciable difference? Not outside of benchmarks.

 

[TheJTrain]

I thought that's the kind of thing I was half-remembering. Well, since the net price difference (after selling the existing pair) looks to only be about a $20 premium for 2x8GB, that's likely the route I'll end up taking.

Thanks all!

 

[BonzaiDuck]

You've made your decision, but that's probably the way I'd go.

There are some decent deals on 2x8GB kits right now. Maybe a year ago or more, you could pay ~$200 for a 4x4 kit, and I'd bought a 2x8 kit of G.SKILL for about $160.

My 2700K rig is fitted with a 4x4 kit of Corsair XMS DDR3-1600's. I'd picked them up as a used set for about half the retail price.

Couple weeks ago, I got the usual daily e-mail ad from Newegg. They were offering a similar G.SKILL DDR3-1866 kit for < $90. I want to "depopulate" my RAM slots leaving two modules -- for a couple reasons.

I think you should get more robust results with a 2x8 kit. Someone apparently found you a spare kit of the Patriots, so that's not a problem, either. Otherwise, for different kits, I'd say try to obtain them from the same manufacturer; you should pick them so the SPD/XMS and voltage specs overlap the old pair.