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19x200 or 21x181? (i7 920 3.8GHz) (Opinions or votes)

Tags:
  • DRAM
  • Intel i7
  • CPUs
  • Overclocking
Last response: in Overclocking
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October 18, 2010 12:29:12 AM

Hi Guys! Quick Question. Whitch is better? A or B?


A:
CPU Ratio 19x
BCLK 200
= CPU 3800MHz, DRAM 1603MHz. (6.8.6.20)


B:
CPU Ratio 21x
BCLK 181?
= CPU 3800MHz, DRAM 1451MHz. (6.8.6.20)




Additional info: (i7 920)
(My Max RAM Specs are 6.8.6.20 1600MHz)

(So if i go with 19x200, my DRAM is faster? but less CPU Ratio. but both ways its still 3.8GHz)
(im not sure how important CPU Ratio is)

Any votes, help would be great thanks :) 

More about : 19x200 21x181 920 8ghz opinions votes

a b à CPUs
a c 100 K Overclocking
October 18, 2010 3:48:57 AM

Well, it won't change much. The main difference I see is the RAM speed, but you should be able to drop the timings at 1451, might have to boost the voltage a bit tho. My RAM is good at 1416mhz CL7 (rated for 1600mhz CL8) but with 1424mhz CL7 (1 baseclock bump) I need a tad more RAM voltage.... so, I would guess it's a similar situation for you.

Other than that, if the temps are better with one over the other you might take that into consideration.
October 18, 2010 9:24:32 AM

thanks wolfram23 .
Both 19x200 and 21x181 run stable at Vcore 1.18v, DRAM 1.6v

im running the RAM at 1.6v, 6.8.6.20, and ether 1451MHz or 1603MHz

(the label on the RAM Says: GSkil 1600 1.6v, 6.8.6.20) so i shouldnt go over that? im already on 1.6v? dont want to burn the ram lol
Related resources
a b à CPUs
October 18, 2010 10:59:25 AM

Dino1080p said:
thanks wolfram23 .
Both 19x200 and 21x181 run stable at Vcore 1.18v, DRAM 1.6v

im running the RAM at 1.6v, 6.8.6.20, and ether 1451MHz or 1603MHz

(the label on the RAM Says: GSkil 1600 1.6v, 6.8.6.20) so i shouldnt go over that? im already on 1.6v? dont want to burn the ram lol


You can change the settings without wrecking your ram as long as you dont raise the voltage too high. Remember 1.65 v is about the maximum you should run your ram on an i7 build. Does your ram run at 1603 mhz at 6-9-6-20? can you drop the tRCD and tRAS timings by one? (tRCD is your 8 and tRAS is the the 20). Over all you will see more benefit from running those timings at 1600 mhz. You will be running the same or nearly the same timings at 15% higher speed. this effectively reduces the latency of your ram more than being able to reduce one or maybe two timing variables by one number.
October 18, 2010 11:29:06 AM

@ewood, I'm running the ram at 1603mhz at 6-8-6-20. (iv not tried 6-9-6-20 as a tRCD of 8 is better then 9 yea?)

So your saying [19x200] 6-'7'-6-19 at 1603mhz? (+ a little more volts)
Or running
October 18, 2010 11:35:16 AM

@ewood, I'm running the ram at 1603mhz at 6-8-6-20. (iv not tried 6-9-6-20 as a tRCD of 8 is better then 9 yea?)

So your saying [19x200] 6-7-6-19 at 1603mhz? (+ a little more DRAM volts)
Or [21x181] 6-7-6-19 at 1mhz? (+ a little more DRAM volts) I beleve this would be less stressful on my RAM??
a b à CPUs
October 18, 2010 11:37:10 AM

Dino1080p said:
@ewood, I'm running the ram at 1603mhz at 6-8-6-20. (iv not tried 6-9-6-20 as a tRCD of 8 is better then 9 yea?)

So your saying [19x200] 6-'7'-6-19 at 1603mhz? (+ a little more volts)
Or running


Sorry, I wasnt very clear at all with what I meant. You can try and lower the timings at 1600 mhz with a little more voltage but they are pretty tight already. I thinking if you chose to run your memory at 1450 mhz you could tighten up the timings. I would run your memory @ 1600 mhz and try and lower the timings, but do it one setting at a time. you could raise the memory voltage to 1.65v first which should help a bit.
October 18, 2010 11:50:14 AM

ewood said:
Sorry, I wasnt very clear at all with what I meant. You can try and lower the timings at 1600 mhz with a little more voltage but they are pretty tight already. I thinking if you chose to run your memory at 1450 mhz you could tighten up the timings. I would run your memory @ 1600 mhz and try and lower the timings, but do it one setting at a time. you could raise the memory voltage to 1.65v first which should help a bit.


yea i see what you mean. i still think that running "19x bclk200, ram 1600" is better then "21x bclk181, ram 1451"

the only thing im not sure about is:
CPU Ratio "19x bclk200 (3.8GHz)" vs "21x bclk181 (3.8GHz)" Which will give the best CUP 3.8ghz overclock?
a b à CPUs
a c 100 K Overclocking
October 18, 2010 3:01:49 PM

Hey just to expand a little, at 1451mhz you could drop the memory timings to maybe 5-7-5-17 or so which is basically as fast as the slower timings at 1600mhz. However, being set to the rated speed is a good thing, since you already know what the proper timings and voltage is so there's no fooling around. 1.65V is the "max", but you can set 1.66 or 1.67 without issue.

As for which ratio is better, the difference will be extremely minimal. If you want to check it out, simply run Intel Burn Test or SuperPI or something like that which will give you an output on the CPU speed. IBT uses GFlops. Simply run both ratios and see if one gives more GFlops than the other (make sure you run them under identical conditions). My guess is the difference would be at most 2 or 3 GFlops (my i5 is in the 50s IIRC, yours is probalby going to be 70s or 80s) so that's very little difference. Overall, the 200 base clock gives you a higher QPI speed, and that's about the only reason it might be faster.
October 18, 2010 10:39:31 PM

Hey thanks wolfram23! Good to know. I'v ran some tests and yes the CPU runs faster (more ops etc) at 19x200. And at lower vcore volts too! All stable and running cool. :) 
a b à CPUs
a c 100 K Overclocking
October 18, 2010 10:53:27 PM

Good stuff!
!