I have a general (I hope) RAM question

[xboxist]

Ok... would either of these configurations be considered "optimal" over the other?

A) 2GB (1GB x2) of DDR2-667

B) 2GB (512MB x 4) of DDR2-800


I ask this because I was told that having fewer sticks yields better performance, but I don't know if there's any truth in this. Basically what I'm asking is... I have the option of using either of the above configurations in my new C2D rig. What would you rather use if it were your system? No overclocking is intended.


Thanks in advance!

 

[deathwalker]

the 1X2 configuration is the right choice here....the key word here is Latency...!!

 

[xboxist]

Originally posted by: deathwalker
the 1X2 configuration is the right choice here....the key word here is Latency...!!

Even though the 1x2 config is slightly slower RAM? Neat, I didn't know that.

 

[xboxist]

Let me extend this one step further.

The 1x2 setup would be Corsair ValueSelect. The 512x4 setup would be performance RAM, Crucial Ballistix.

Would you still choose the DD2-667 stuff?

 

[Atheus]

Having 2 sticks allows you to use dual channel while 4 sticks does not. Never use 4 sticks.

Why are those the only two options anyway? Can't you get 2*1GB of DDR2-800?

The 1x2 setup would be Corsair ValueSelect. The 512x4 setup would be performance RAM, Crucial Ballistix.

You said 'no overclocking intended' so what's the point in buying high performace 667 over the regular 800? Even if we assumed they were both 2*1 setups, the 667 would still be slower and more expensive.

 

[Boyo]

4 Sticks of RAM is actually slower than 2 sticks of dual memory. Get the best you can at 2x 1GB with low latencies, or at leat what you can afford at these prices.

 

[Noubourne]

No 2x1GB of DDR2 667 is NOT the right choice.

It's easier to manufacture smaller sticks of RAM with lower latencies. If you want better latency, you're more likely to get it with the 4x512. If you want better performance, go with the faster RAM (higher bandwidth). The DDR2 800 sticks MIGHT (not saying they do) have a higher CAS latency rating on them, but since they're operating at a higher clockspeed, that will often cancel it out (unless they have a REALLY high latency).

The number of sticks you get has absolutely no affect on performance. It will only determine whether or not it is possible to add more RAM in the future. If you fill all four slots with RAM, you'll need to buy bigger sticks (1Gb vs. 512MB) in order to add RAM to the machine in the future. Ifyou had 2 slots open, you could just buy more RAM and add it without having to re-buy what you already had in there.

If I had to choose between the the two choices above (and I wouldn't), I would pick the DDR800 hands down. Anyone who says 2Gb of DDR2 667 is better than 2Gb of DDR2 800 without knowing the specs is either insane, or trying to sell you something. For under $200 you can get some CAS 4 DDR2 800 in 2x1Gb, and you won't find CAS 3 DDR2 800 even with the 4x512MB combo, so I just wouldn't buy it - it doesn't save you any money.

 

[xboxist]

Originally posted by: Atheus
Having 2 sticks allows you to use dual channel while 4 sticks does not. Never use 4 sticks.

Why are those the only two options anyway? Can't you get 2*1GB of DDR2-800?

The 1x2 setup would be Corsair ValueSelect. The 512x4 setup would be performance RAM, Crucial Ballistix.

You said 'no overclocking intended' so what's the point in buying high performace 667 over the regular 800? Even if we assumed they were both 2*1 setups, the 667 would still be slower and more expensive.

You're assuming that I'm shopping for RAM. I already have both setups of RAM in my possession from previous endeavors. I'm buying nothing, and I have both options available to me to use.

 

[xboxist]

Well, I'm confused. Noubourne is saying using the 4x512, hands down. Atheus says that dual-channel will not "work" with 4 sticks. I'm not sure what this means for me.

 

[xboxist]

Let me eleborate upon my position. I owe you that much. Maybe it will better help understand where I'm coming from.

About a year ago I won the 512x4 DDR2-800 in a contest. But I didn't have the funds to build a new system around it. So I just held onto them.

A month ago I started shopping for a new Core 2 Duo rig. The RAM that I won has a voltage of 2.2v. When I researched what board to buy, most of the boards (at the time) that supported that kind of voltage were all around $250 or higher. That was too pricey for my tastes, so I decided to just buy a cheaper MB (Intel DP965), and some cheaper 1.8v RAM to use with it. I thought I could pass along the RAM that I won to a friend or something. This cheaper RAM is option A) in my topic post.

Since then, I've learned that the DP965 board sucks ass, and I returned it. I now have a Gigabyte DS board coming. And I've read that this will support the RAM that I won (2.2v). So I'm left with this new board that will house either configuration of RAM. And I'm not sure what to use. The 1.8v Corsair RAM can STILL BE RETURNED for a refund, if needed. But I want to use the RAM config that will work best for me. So yeah, I could save $150 and just use the 512x4 Ballistix. But I wanted your opinions first.

 

[Noubourne]

This is Intel's 965 or 975 chipset. It's not the early Athlon 64 on-die memory controller that would fail to run 4 DIMMS at DDR400 and rate them at DDR333 instead, or that could finally do DDR400 with 4 DIMMS but not at 1T Command Rate.

You can run dual channel with all four slots filled on 965 Express or 975. Period. It supports up to 8GB RAM. It doesn't support up to 4GB of RAM in Dual Channel Mode (2Gbx2), and up to 8GB in single channel mode - it just does 8GB PERIOD.

Atheus is wrong.

 

[Noubourne]

Use the Ballistix. Period.

 

[Fishy007]

Originally posted by: Atheus
Having 2 sticks allows you to use dual channel while 4 sticks does not. Never use 4 sticks.

Sorry, what?
You may want to come here and tell that to my system...my system which is running 4x512mb of ram in Dual Channel.

As for the OP, the 4x512 will be faster (depending on the system you're putting it in). The latency difference you see between the 2 stick setup and the 4 stick setup will not be enough to offset the difference in speed.

Hell, if you want real numbers pop one set in, run a benchmark, pop another set in run another benchmark. Take the faster set.

 

[Atheus]

I stand corrected then - I guess you can use 4 sticks in dual channel with the new Intels. I haven't played with a Conroe setup yet so I didn't know.

It has always been the recieved wisdom that 2 sticks are more stable than 4 sticks though, due to the fact that memory controllers are designed with 2 sticks in mind, so I still find it a little hard to believe that performance is identical.

/Edit: I see reports in other forums that 4 sticks will not run 1T command rate under Athlon _or_ Conroe - can anyone confirm or deny?

Hell, if you want real numbers pop one set in, run a benchmark, pop another set in run another benchmark. Take the faster set.

OP - do this. I would be interested in results.

 

[Fishy007]

Originally posted by: Atheus
I stand corrected then - I guess you can use 4 sticks in dual channel with the new Intels. I haven't played with a Conroe setup yet so I didn't know.

Just FYI, I've *always* used 4 sticks. Ever since Hyperthreading came out. I've personally owned 3 different HT chips (with 4 sticks in use) and built dozens of others. I don't know if I'm not getting peak performance because of this, but it does work. I've also always had Intel chips and Intel controllers.

 

[xboxist]

Ok. Thanks guys for clearing this up. Here's what I'm going to do:

Test with...

1) 2GB DDR2-800, Ballistix (512mb x4)
2) 2GB DDR2-667, Corsair ValueSelect (1gb x2)
3) 2GB DDR2-667, Ballistix (512mb x4) -- my friend has this, I will borrow to test since I'm already going to be testing anyway.

Hope to do this in the next couple of days or so. I'm curious to see how #2 and #3 compare to one another. It will basically be "4 sticks, performance RAM" vs. "2 sticks, standard RAM".

Is there a suite or something I can download to run these tests?

 

[Fishy007]

SiSoft Sandra has specific memory speed tests. I'm not sure how good the tests are though. Or perhaps an overal benchmark of the system might be better. For that, I've seen people use PCMark and 3DMark, but I've never used them myself.

 

[mathew7]

The problem with 4 sticks relates to the memory bus. In dual-channel mode, there are 2 memory channels (dooh!). If you use 4 sticks, each channel has to deal with 2 sticks. So these 2 sticks will be connected to the SAME bus lines, which degrades the electrical signals. I personally had a problem with 2 sets of DDR400 memories on an Athlon64 running DDR200, but no problems with same sets on an intel 865.
But on DDR2 SDRAM, they put something called "bus termination" on the memories to combat this problem. I don't know the actual details, but since I read that I froze on the idea that 2sticks/channel is no more of an issue.

 

[Blain]

2 large sticks over 4 smaller sticks any day of the week.