16GB kit + 16GB kit: Combination with other memory kits is not recommended.

[bdbarb]

Hello,

I am new to the forums and have a question. Please post links if this has already been discussed.

I bought 16GB of Dual channel ram F3-1866C10D-16GAB to run on a dual channel Z68 motherboard. The ram is officially qualified to run on this board. Everything is running great. I ordered another set to run 32GB in dual channel. I would assume the 4x8GB kits are simply two 2x8GB kits tested together before being shipped out and are hopefully the same chips in either kit. Will I have any kind of issue with these?

On Newegg there is the following disclaimer:

Combination with other memory kits or modules (even with same model number) is not recommended to avoid any compatibility issues.

[AndrewDaniels]

It should work, you just won't be able to use XMP and you'll probably have to enter timings manually. I'm still learning but there lots of people on here that will be able to help you.

[Tradesman]

Very true and you'll see it throughout the forums here. ANY time you mix sets, even of the same model it can be problematic, additionally XMP won't work. XMP programming in the sticks is done by the individual set. While this won't show up on the base timings, when you get to the advanced/secondary timings is where problems often arise...some mobo BIOSs can set things fairly well, but most don't under Auto. Of particular note is the tRFC setting, a 2 stick set may require 125 or so, yet a 4 stick setup will need 170ish. You also normally need to manually adjust the MC (Memory Controller) voltage and the DRAM voltage. If already ordered, when you get them, give 'em a try and if problems give us a shout

[bdbarb]

Thanks for the replies!

I'm looking for the settings for the quad kit F3-1866C10Q-32GAB but the site product page doesn't list the XMP settings. Anyone know where to find the settings for this 32GB kit? http://gskill.com/products.php?index=487

I also would like to leave the voltage at the rated 1.5v to help keep heat low on the system.

[Tradesman]

It's going to show the base timings, but the secondary/advanced timings will vary from mobo to mobo and BIOS to BIOS, think the following should work

tWR 14
tRFC 255
tRRD 6
tWTR 7
tRTP 7
tFAW 25

tRFC may have to go up a bit. and by all means, try the voltage at 1.5 initially, with mixed sets though you may have to raise it, the DRAM voltage won't affect temps as much as having to raise the MC voltage, so I try and start with the DRAM

[bdbarb]

I have AIDA64 and looking at the current timings for just the 2 sticks are below. I have to wait for the other 2 sticks to get here as I just ordered them yesterday! I really hope this is going to be an easy process as I am still within the return with restocking fee period to exchange for a 4x8GB kit.


Memory Timings:
CAS Latency (CL) 10T
RAS To CAS Delay (tRCD) 11T
RAS Precharge (tRP) 10T
RAS Active Time (tRAS) 30T
Row Refresh Cycle Time (tRFC) 243T
Command Rate (CR) 2T
RAS To RAS Delay (tRRD) 6T
Write Recovery Time (tWR) 16T
Write To Read Delay (tWTR) 8T
Read To Precharge Delay (tRTP) 8T
Four Activate Window Delay (tFAW) 26T
Write CAS Latency (tWCL) 7T

[Tradesman]

When they arrive, give it a try and then let us know and we can go from there

[bdbarb]

As much as I enjoy a good challenge, I called for an RMA on the 2 16GB kits and ordered a 4x8GB Dual Channel kit. Really great price on them right now, actually came out to less than the 2 kits combined even considering my shipping costs to send the 16GB kit back. I've learned my lesson plenty of times over with computer parts and I'm not on the payroll to test out kits. The last time I tried I wound up with 1600 ram that was only stable at 1333.

Thanks for your help! It's good to know these forums are here.

[Tradesman]

No problem, we're always around, let us know how you like the set when it comes in

[bdbarb]

Tradesman I got to thank ya for wanting to help out. It is insane the price of these modules compared to a year ago! At no price difference it just seems easier to deal with and easier to support if I need it to go with this quad kit. With a 40 dollar off code it beat out my two kits by 30 dollars. http://www.newegg.com/Product/Produc...82E16820231562

[Tradesman]

Definitely - go for it! I remember during a big price drop and a sale I had just gotten a 16GB set of 1600, a day later a sale, bought 1866 and returned the 1600, then about 1 week 10 later, another sale and a coupon so kicked up to 2133/16GB ended up costing total about $10 more than the original 16GB/1600 where the diff had been like $70 when I originanlly ordered the 1600 set

[bdbarb]

I was looking on another site about ram, performance comparison of latency vs mhz. A user Knufire mentions: If you want to have a good measure to compare sets, divide the CAS Latency (first number in the timings) by the speed. 1600 CL7 = 1600/7 = 228.6 is better than DDR-1866 CL9 = 1866/9 = 207.

Going by this I decided to throw together a list of 32GB kits (4x8GB) per what is currently available price wise on the egg.
na means the memory was not available.
MHZ /CAS = Score... Price on the egg.
2400 9 266.67 na
2400 10 240.00 309
2133 9 237.00 299
2400 11 218.18 303
2133 10 213.30 314
1866 9 207.33 224
2133 11 193.91 259
1866 10 186.60 189(149 sale)
1600 9 177.78 179
1866 11 169.64 na
1600 10 160.00 159
1333 9 148.11 139
1600 11 145.45 154
1333 10 133.30 na
1333 11 121.18 na

[Tradesman]

Good comparison, I'm sure many will appreciate the info,

Thanks!

[bdbarb]

FYI and since we are on a G Skill forum I might as well fill ya in. I got the F3-1866C10Q-32GXL G Skill kit which is on sale with a promo code for only 149. Woohoo I'm excited to see that number in my task manager. Girlfriend rolls her eyes at me and asks why I would spend that much money on a box sitting in my living room. :P

[Tradesman]

Great prices great DRAM....32GB is sweet, that's what I have in both my main rigs, getting a big itch to try X79 and 64GB........have fun!