What memory to choose for a 2.4C (Costa Rica, SL6Z3), IC7 Max3 and Thermalright SP-94???

[Brian Madsen]

Hi.

I have recently bought these components for my new rig. But I'm still missing the memory - I can't decide what to buy!

At first I was planning a 3.6 GHz overclock with the 5:4 DRAM ratio. That would give a memory speed of 240 MHz. I concluded that the OCZ EL DDR PC3700 Dual Channel Gold would be the memory to get. I think it is reasonable to expect a 7 MHz overclock at default 2-3-3-7 timings. Have heard of other people running a SL6Z3 at 3.6 GHz with a SP-94.

But now I'm having second thoughts. I know that a memory ratio of 1:1 is to be preferred due to synchronous speeds. But with which memory can I expect a decent OC, @+3.2 GHz? Should I look at OCZ PC4000 Dual Channel Gold or OCZ PC4200 Premier Dual Channel?

I have read the article at
http://www.tomshardware.com/motherboard/20030812/index.html and the forums at Abit's website and at Overclockers.com. I'll be a bit disappointed if I end up with some PC4200 memory, which can't go significantly faster than 267 MHz.

Any advice/comments/suggestions.

Tia

Brian Madsen

 

[Skid]

I understand your problem, but you're going to have a hard time finding any ram that will reliably overclock a 2.4 to 3.2+ at 1:1. If you did, the higher latency would kill most of the gain you'd get by running synchronous, and you still wouldn't be pushing the cpu to the max.

Check the Abit forums at http://forum.abit-usa.com/ and you'll see most people overclocking 2.4s opt for the lowest latency ram they can run at 5:4 and push the fsb until the cpu squeals.

On my IC7, I'm running Buffalo Tech PC3700 (same Winbond BH-5 modules as Mushkin PC3500 Level II Black, but lots cheaper.)

Running 5:4, 275/220. CPU is 3.3 ghz, memory at 2,3,2,6. 100% stable and fast enough for any sane person. Me, I'd like a little more ;>)

"Brian Madsen" wrote:

Hi.

I have recently bought these components for my new rig. But I'm still missing the memory - I can't decide what to buy!

At first I was planning a 3.6 GHz overclock with the 5:4 DRAM ratio. That would give a memory speed of 240 MHz. I concluded that the OCZ EL DDR

PC3700

Dual Channel Gold would be the memory to get. I think it is reasonable to expect a 7 MHz overclock at default 2-3-3-7 timings. Have heard of other people running a SL6Z3 at 3.6 GHz with a SP-94.

But now I'm having second thoughts. I know that a memory ratio of 1:1 is to be preferred due to synchronous speeds. But with which memory can I expect a decent OC, @+3.2 GHz? Should I look at OCZ PC4000 Dual Channel Gold or OCZ PC4200 Premier Dual Channel?

I have read the article at
http://www.tomshardware.com/motherboard/20030812/index.html and the forums at Abit's website and at Overclockers.com. I'll be a bit disappointed if I end up with some PC4200 memory, which can't go significantly faster than

267

MHz when my aim is to overclock the heck out of this rig.

Any advice/comments/suggestions?

Tia
Brian Madsen

 

[Brian Madsen]

"Skid" wrote:

I understand your problem, but you're going to have a hard time finding any ram that will reliably overclock a 2.4 to 3.2+ at 1:1. If you did, the higher latency would kill most of the gain you'd get by running synchronous, and you still wouldn't be pushing the cpu to the max.

Quote Toms Hardware
(http://www17.tomshardware.com/motherboard/20030812/ddr500-01.html):

"A mere 3 MHz of extra FSB speed is enough to outperform the optimized system with run-of-the-mill timings, bla bla bla...."

As I understand this statement, a higher fsb is to be preferred rather than tighter rimings.

The question narrows down to which of these two setups is the fastest (in every day use):
A 2.4c overclocked to 3.6 GHz with a DRAM ratio of 5:4 with DDR at 240 MHz with timings of 2-2-2-5 or a 2.4c overclocked to 3.36 GHz with a DRAM ratio of 1:1 with DDR at 280 MHz with timings of 3-3-4-7.

Brian Madsen

 

[Skid]

"Brian Madsen" wrote:

"Skid" wrote:

I understand your problem, but you're going to have a hard time finding any
ram that will reliably overclock a 2.4 to 3.2+ at 1:1. If you did, the
higher latency would kill most of the gain you'd get by running synchronous,
and you still wouldn't be pushing the cpu to the max.

Quote Toms Hardware
(http://www17.tomshardware.com/motherboard/20030812/ddr500-01.html):

... than tighter rimings.

The question narrows down to which of these two setups is the fastest (in every day use):
A 2.4c overclocked to 3.6 GHz with a DRAM ratio of 5:4 with DDR at 240 MHz with timings of 2-2-2-5 or a 2.4c overclocked to 3.36 GHz with a DRAM ratio of 1:1 with DDR at 280 MHz with timings of 3-3-4-7.

The Tom's Hardware review is all but irrelevant to this discussion, as he only used two test setups -- a stock 3.2g 1:1 at 200 fsb and an overclocked
2.6 running 1:1 at 250 fsb. It doesn't take a rocket scientist to figure out which will come out ahead in that race, as the second system has a small edge in cpu speed and a huge advantage in memory bandwidth.

I can tell you that my system running 5:4, 275/220, at 3.3 ghz, 2,3,2,6, turns in better scores across the board than either of the systems in that test.

Most of the standard reviews of mobos and memory fail to compare using different cpu/ram ratios. But if you'll check the forums at Tom's, or www.anandtech.com, or www.overclockers.com or www.hardocp.com or www.forums.abit-usa.com you'll find a lot of individual benchmarks and a general consensus.

All things being equal, 1:1 offers better performance than 5:4. But the ram is the limiting factor, especially when you're working with a 2.4 or 2.6 with a low multiplier.

In my experience, if you can get the fsb just 6-7 mhz higher using 5:4, you'll get better overall performance than at 1:1.

Not only that, but if the ram you need to run 1:1 at 250 or above is CAS 2.5 or 3, you can often get higher memory benchmarks running 5:4 at CAS 2.

All these reasons -- plus the high cost of PC4000-4200 -- help explain why a lot of experienced overclockers go for memory that will run tight timings at 210-240 mhz and push the cpu to its limits at 5:4.

Here is a graphic from a review that shows one factor in the equation:

http://www.hardocp.com/images/articles/1062141591eE98nfjMXY_4_26.gif

The top two bars show Sandra memory benchmarks for a 3.2g P4 running 1:1 at 200 vs. a 3.0 running at 5:4. Both are using the same PC 3200 running the stock 200 mhz with the same timings.

Guess which is higher? Also note how much benefit the 3.0 gets over the same cpu at stock 1:1 because of the faster cpu bus, without bumping the memory speed at all.

The key to answering the hypothetical you pose is the phrase "in everyday use." Most games and benchmarks depend most on cpu speed, and if you can get the cpu higher at 5:4 it's going to score higher in almost everything but memory benchmarks.

 

[Brian Madsen]

The Tom's Hardware review is all but irrelevant to this discussion, as he only used two test setups -- a stock 3.2g 1:1 at 200 fsb and an overclocked 2.6 running 1:1 at 250 fsb. It doesn't take a rocket scientist to figure out which will come out ahead in that race, as the second system has a small edge in cpu speed and a huge advantage in memory bandwidth.

Oohh, I've missed that fact.

I can tell you that my system running 5:4, 275/220, at 3.3 ghz, 2,3,2,6, turns in better scores across the board than either of the systems in that test.

Most of the standard reviews of mobos and memory fail to compare using different cpu/ram ratios. But if you'll check the forums at Tom's, or www.anandtech.com, or www.overclockers.com or www.hardocp.com or www.forums.abit-usa.com you'll find a lot of individual benchmarks and a general consensus.

All things being equal, 1:1 offers better performance than 5:4. But the ram is the limiting factor, especially when you're working with a 2.4 or 2.6 with a low multiplier.

In my experience, if you can get the fsb just 6-7 mhz higher using 5:4, you'll get better overall performance than at 1:1.

Not only that, but if the ram you need to run 1:1 at 250 or above is CAS 2.5 or 3, you can often get higher memory benchmarks running 5:4 at CAS 2.

All these reasons -- plus the high cost of PC4000-4200 -- help explain why a lot of experienced overclockers go for memory that will run tight timings at 210-240 mhz and push the cpu to its limits at 5:4.

Here is a graphic from a review that shows one factor in the equation:

http://www.hardocp.com/images/articles/1062141591eE98nfjMXY_4_26.gif

The top two bars show Sandra memory benchmarks for a 3.2g P4 running 1:1 at 200 vs. a 3.0 running at 5:4. Both are using the same PC 3200 running the stock 200 mhz with the same timings.

Guess which is higher? Also note how much benefit the 3.0 gets over the same cpu at stock 1:1 because of the faster cpu bus, without bumping the memory speed at all.

The key to answering the hypothetical you pose is the phrase "in everyday use." Most games and benchmarks depend most on cpu speed, and if you can get the cpu higher at 5:4 it's going to score higher in almost everything but memory benchmarks.

Thanks a lot for this explanation. It answers most of my questions.

But what memory do You recommend, Skid? It must be able to run at 240 MHz with the tightest possible timings. I live in Europe, so the accessibility isn't the best.

Brian

 

[Skid]

"Brian Madsen" wrote:

Thanks a lot for this explanation. It answers most of my questions.

But what memory do You recommend, Skid? It must be able to run at 240 MHz with the tightest possible timings. I live in Europe, so the accessibility isn't the best.

That's a very tall order. I suggest you read the memory reviews at www.amdboard.com (ignore the AMD part, they compile reviews from all over on both platforms) and check the forums at www.forums.abit-usa.com to see what others are using on the same board.

I really like my Buffalo Tech PC3700, but with the 2.8v limit on my IC7 I can't get it much past 220 at CAS 2, or 225 at CAS 2.5 without occasional errors. That is fine for me, because my 2.4 also gets squirrely at much above 3.3ghz.

At 275/220 everything is 100% rock solid.

Maybe the extra voltage headroom on the MAX would help, or maybe there's ram out there with more headroom. I can't recommend what I haven't tried.

Happy hunting.

 

[Brian Madsen]

Found some Mushkin PC-3500 Level II Dual Pack with SPD timings of 2-3-2-6 for Intel chipsets (875 or 865) and 2-2-2-6 for nForce2. I have read of some people running it at 2-2-2-5 at 240 MHz - are they just really lucky, or could I also expect this. I believe these modules utilize the Winbond BH-5 chips, which should perform really well in Intel rigs.

Just to sum up:

Buffalo PC3700, CAS Latency of 3.
Corsairs XMS 3700 has timings of 3-4-4-8.
Geil PC-3700 has timings of 2.5-3-3-7.
Kingston HyperX 3700 has timings of 3-4-4-8.
Kingston HyperX 3500 has timings of 2-3-3-7. The reviews I have read aren't that impressive, though. OCZ EL DDR PC-3700 Dual Channel Gold has timings of 2-3-3-7.

At the moment Mushkin PC-3500 Level II or OCZ PC-3700 Gold are the best options.

Brian

 

[Skid]

You can't always judge by the manufacturer's recommended timings, some are very conservative to guarantee stability, others are artificially loose to allow higher speed ratings. Some bait and switch, with one set of timings built into the SPD for compatibility, and another "recommended" set for those who want better performance.

The result, which adds still another layer of complexity to ram shopping, is that many sticks can run tighter timings at lower speeds, others can't.

Two cheap examples:

Crucial adheres faithfully to the JEDEC spec for PC3200 and recommends CAS 3, but can almost always run 2.5 and clocks as high as some PC3500.

Buffalo Tech PC3700 has the same Winbond BH-5 as Mushkin PC3500, and on my IC7 runs the same 2,3,2,6 at 220+ mhz. It needs 2.5 or 3 to get to 230+, and I don't really know how high it can go because my board can't feed it more than 2.8v and my cpu is maxed out using the 5:4 ratio.

Mushkin is really good stuff, though expensive. Even so, I have a hard time believing 2,2,2,5 at 240, heat spreaders or not.

Meanwhile most of the so-called PC4000 sticks flat won't run below CAS 3.

It's interesting, but not surprising, that both the top two choices on your list use memory modules originally certified for 200 mhz. OCZ cherry picks Samsung chips and grinds off the top layer to improve heat transfer. Mushkin bought out what was left of the discontinued BH-5 and bumped it up the same way overclockers had been doing when it was commonly sold as PC3200.

Like the old carney says, "You pays your money, and you takes your chance."

"Brian Madsen" wrote:

Found some Mushkin PC-3500 Level II Dual Pack with SPD timings of 2-3-2-6 for Intel chipsets (875 or 865) and 2-2-2-6 for nForce2. I have read of some people running it at 2-2-2-5 at 240 MHz - are they just really lucky, or could I also expect this. I believe these modules utilize the Winbond BH-5 chips, which should perform really well in Intel rigs.

Just to sum up:

Buffalo PC3700, CAS Latency of 3.
Corsairs XMS 3700 has timings of 3-4-4-8.
Geil PC-3700 has timings of 2.5-3-3-7.
Kingston HyperX 3700 has timings of 3-4-4-8.
Kingston HyperX 3500 has timings of 2-3-3-7. The reviews I have read aren't that impressive, though.
OCZ EL DDR PC-3700 Dual Channel Gold has timings of 2-3-3-7.

At the moment Mushkin PC-3500 Level II or OCZ PC-3700 Gold are the best options.

Brian

 

[Brian Madsen]

I think I'm going for the OCZ EL DDR PC-3500 Dual Channel Platinum Limited Edition. Anandtech managed to OC it to 466 MHz DDR with CLs 2-2-3-8. At 433 MHz DDR it was at 2-2-2-5.

Brian