Dumb(?) memory questions

[forkbomb]

(Note to get this over with: I'm not trying to start a manufacturer war here. I'm asking if something would work, not what manufacturer is on your personal crap-list. After all, "religious topics are not permitted." )

I'm not a serious overclocker or performance-obsessive but I need more memory. A memory upgrade has been a long time coming for my main rig. I'm sitting at a peasant-like 2GB. Came into some cash so I figure why not.

Anywho, mobo is a P5N-E SLI. It's aging but still serviceable and in good shape. Board's memory standard is PC2 6400 (and I think one other slower 240pin DDR2 standard but I'd like to stick with 6400).

Right now I have 2GB of Corsair XMS2 memory, 2*1GB bought as a dual-channel kit. Stats are:
CAS lat: 4
Timing: 4-4-4-12
Voltage: 2.1V

The manual says the board maxes at 8GB, which must be arrived at by 4*2GB (no more than 2GB in a single slot). I'm thinking on buying two sets of OCZ Reaper, and not because I have a fetish for heat sinks.
http://www.newegg.com/Product/Produc...82E16820227267

Questions are these:

1) The OCZ Reaper has the same speed, CAS latency, and voltage as my current kit, but different timings. Namely the Reaper has 4-4-4-15. Is that a problem? My Mobo's BIOS and manual has a bunch of settings for memory timing but it's Greek to me. There are a couple memory settings that allow you to set to 15, and there are also Auto settings for everything. Suffice it to say I think I could change the timings via my BIOS but I have no idea if that's good for the memory or the board.
2) I see some kits marketed as quad-channel kits. Are these really going to offer any appreciable benefit over getting two sets marketed as dual-channel kits? Or is it marketing shenanigans?

[GoinEasy9]

I don't have opinions on the benefits of one memory over another, but, when populating my Asus boards I always check to see if it's on their approved list.
Or look for Asus approved links like this:
http://www.crucial.com/upgrade/compa...+SLI/list.html

[forkbomb]

*shrug* I have had Corsair XMS2 in it for years with no problems (stability or otherwise), and it's not specifically on the approved memory list in the manual. The memory I have in it appears to be discontinued, at least on the egg.
http://www.newegg.com/Product/Produc...82E16820145034

After thinking about it, I could live with 6GB (until I have money to build a new box) and it doesn't make sense to blow $140+ on an obsolete memory standard on an aging motherboard just to get 8GB. A friend in meatspace says you can mix memory with different latencies and timings safely, but I'm leery to try it even if I grabbed more Corsair XMS2. I don't need top-notch performance but I don't want to risk burning out hardware (if that's even possible from mixing memory). So on second thought would it be safe to mix the XMS2 set I have with this:

http://www.newegg.com/Product/Produc...82E16820145184

(The speed is the same - 800Mhz - but the CAS latency, timings, and voltage are all different.) I know "best practice" is to match as precisely as possible but at this point I'm fine with it working rather than working optimally. I'd even be able to live with 4GB if I got a new 2x2 set and just ended up taking out what I have if mixing led to stability issues.

Maybe I'll just do that and bide my time. Grr. I hate these types of decisions.

[stevea]

Originally Posted by forkbomb

(Note to get this over with: I'm not trying to start a manufacturer war here. I'm asking if something would work, not what manufacturer is on your personal crap-list. After all, "religious topics are not permitted." )

OCZ is a quality name - no complaints there.

...
Right now I have 2GB of Corsair XMS2 memory, 2*1GB bought as a dual-channel kit. Stats are:
CAS lat: 4
Timing: 4-4-4-12
Voltage: 2.1V

The manual says the board maxes at 8GB, which must be arrived at by 4*2GB (no more than 2GB in a single slot). I'm thinking on buying two sets of OCZ Reaper, and not because I have a fetish for heat sinks.
http://www.newegg.com/Product/Produc...82E16820227267

Questions are these:

1) The OCZ Reaper has the same speed, CAS latency, and voltage as my current kit, but different timings. Namely the Reaper has 4-4-4-15. Is that a problem? My Mobo's BIOS and manual has a bunch of settings for memory timing but it's Greek to me. There are a couple memory settings that allow you to set to 15, and there are also Auto settings for everything. Suffice it to say I think I could change the timings via my BIOS but I have no idea if that's good for the memory or the board.
2) I see some kits marketed as quad-channel kits. Are these really going to offer any appreciable benefit over getting two sets marketed as dual-channel kits? Or is it marketing shenanigans?

1) No problem. That final number is the tRAS timing. The memory controller has to wait at least that many (12 vs 15) cycles before disabling the row select. So your older mem requires 0 delay (4+4+4 = 12), and the OCZ's require the RAS to remain for another 3 cycles (15 - (4+4+4)). Most 4 way mem controllers allow 2 sets of timing - so long as the pair is the same timing it works. Nearly all BIOSes will choose the slowest memory settings if you mismatch chips withing a timing set (but BIOSes have bugs).

2) Quad matched sets are a good idea if you intend to overclock to the limits. That way all 4 should fail at close to the same figure. If you chose 2 pairs, you might end up with a great pair and a mediocre pair and you get little advantage over the slowest parts. Not a scam, but primarily meant for guys who live in their Mom's basement and like to drop two grand every year on the latest vid cards or the maximum core-count CPU.

Excellent price on the OCZ. If you choose to get one pair of OCZ, just be sure you populate the mem slots according to the pair-wise interleave sets (IOW read the MOBO manual).

[forkbomb]

Thanks stevea. I'm thinking I'll just go with one set of 2GB*2 instead of gunning to max it out. Now to decide between the OCZ or another set of XMS2 so as to not mix memory from different vendors.

[jpollard]

You can also play games with the slower memory - put it first in order
so that when the BIOS scans, it finds the slow one right off. That way
even if the BIOS is buggy, it will most likely get the slow numbers.

[Dan]

All that being said, strictly from an aesthetics point of view ...

This is a helluva lot more fun to look at than this. <....>

[JamesNZ]

Or you could just go shopping for a computer Isn't it odd how women like shopping for softwear(pun intended) and geeks like shopping for software and hardware

[forkbomb]

Shopping for a computer? What kind of noob does that!? I shop for parts and then build a computer.

In any event I have enough scratch for a memory upgrade. Not enough for a brand new rig. Hopefully my desktop can limp along for another 6 months or so.

[JamesNZ]

Originally Posted by forkbomb

Shopping for a computer? What kind of noob does that!? I shop for parts and then build a computer.

Forgive a poor noob who does not yet know the difference between clockspeed and FSB cycles