Better Frequency or Timings in Haswell Memory Overclock

[mattchid]

I'm looking for input on where the performance gains will be on a memory overclock, in the timings or the frequency, or a mix of both.

I'm making an earnest attempt to overclock some Corsair Vengence (low profile) memory. The retail settings are DDR3 1600 11-11-11-30 timings. The voltage is 1.5, and even with the overclocks I haven't gone higher than that. I've established what I believe to be the two alternative overclocks, both of which pass 1000% Memtest 4.0 stress tests:
1) 2133 @ 11-11-11-27 T1, and I can't seem to get the timings lower at all, I get errors
2) 1600 8-8-8-24 T1
I'm sure there's workable speed and timings in between, but my question is, which is faster/better/etc.?

Rest of the system:
i7 4770k (stock speed right now, i'm planning a modest overclock to 4.4 Ghz
Z87 Asus Gryphon motherboard

All help appreciated, and if someone wants to comment (who feels they know definitively) whether Haswell benefits more from frequency or tighter timings, i'd appreciate it.

 

[Tradesman1]

Overall, it's not worth trying with those sticks, a base spec of 1600 is generally CL9, CL11 indicates the ICs (memory chips are on the weak side to begin with), could try 1600 and CL10 (which is still slow for 1600) will prob need an extra + 0.06 to DRAM voltage and about the same to the MC voltage

 

[mattchid]

Overall, it's not worth trying with those sticks, a base spec of 1600 is generally CL9, CL11 indicates the ICs (memory chips are on the weak side to begin with), could try 1600 and CL10 (which is still slow for 1600) will prob need an extra + 0.06 to DRAM voltage and about the same to the MC voltage

You say it's not worth trying, but these two are already tried and succeed. Both of these settings have passed Memtest 4.0 to 1000%... they are stable at these speeds. So given the choice of speeds, with the frequency and timings as the priority on one or the other, which produces the most desirable result?

 

[Tradesman1]

Of those two the 1600 set, it roughly equates to 2133/9 so 2133/11 has the wider bandwidth but the clock rate is much slower.........what brand and model of sticks are these? If they are spec 1600/11 you got an outstanding pair..Can find model number in CPU-Z in the SPD tab listed as Part Number

 

[mattchid]

The model is CML8GX3M2B1600C. And I must admit, I'm surprised by your answer.

 

[Tradesman1]

I'm surprised by the sticks, may have to get a pair to play with

 

[mattchid]

If I take your answer to its logical end, then timings are more important that frequency, as the frequency difference is 500 mhz. The way you answered the question implied there was a logical convertable number for comparing 1600 with those timings to 2133 and those timings, you compared the 1600 timings to being like 2133 cas9.

 

[Tradesman1]

Generally with DRAM sticks are looked at in a stairstep fashion from the starting point we'll say 1600/8 the DRAM performance remains just slightly higher when taking sticks up 1 step each of freq and CL....the biggest increase comes from the additional bandwidth of the higher freq so we would progress as such:

1600/8 1866/9 2133/10 2400/11 2666/12

(and just noticed, had a typo up there, should have been 2133/10 instead of 9, sorry bout that)

with performance sticks (what I was thinking of in the step fashion) it's generally

1600/7 1866/8 2133/9 2400/10 2666/11

 

[mattchid]

Generally with DRAM sticks are looked at in a stairstep fashion from the starting point we'll say 1600/8 the DRAM performance remains just slightly higher when taking sticks up 1 step each of freq and CL....the biggest increase comes from the additional bandwidth of the higher freq so we would progress as such:

1600/8 1866/9 2133/10 2400/11 2666/12

(and just noticed, had a typo up there, should have been 2133/10 instead of 9, sorry bout that)

with performance sticks (what I was thinking of in the step fashion) it's generally

1600/7 1866/8 2133/9 2400/10 2666/11

That makes good sense, thanks. Upon further testing i found the following as stable
1600 8-8-8-24-T1
1866 9-9-9-24-T1
2133 11-11-11-27-T1
If 1600 at these timings is better than 2133, because of the high timings, then is 1866 at these timings the best of the three? One last question, is it a fair rule of thumb that any timing being lower is desirable? Looking at other RAM timings on retail models, its generally 1866 9-10-9-27, mine are 9-9-9-24, is it fair that any decrease is beneficial?

Thanks.

 

[Tradesman1]

1866 would be the best with a slight bandwidth +.............you're going to have me spending money here, where did you get your set?

 

[mattchid]

I got the set at Microcenter, I got my set for $59, but that was with combo discount for buying an i7 4770k.

What do you mean "with a slight bandwidth +............."?

 

[Tradesman1]

The 1866 has more bandwidth overall so it gets a plus as otherwise performance near eual at those steps