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I7 selection question

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August 16, 2009 7:32:06 PM

Hey guys, I don't know if there is a fact answer to this or if it is opinion, but I am getting a new system and don't know what processor to get.

My options are this:
i7-975 @ $760 more than the 920
i7-950 @ $290 more than the 920
i7-920 @ Base price

ALSO, same price on overclocking them as follows:
45$ for 10% OC
90$ for 20% OC

Any ideas on what the best price combo would be for performance? ** I WILL NOT overclock on my own in order to save up to 90 bucks...I am a total newb and just don't want to.

My plan right now is to do the 920 with the 20% OC.

How much more can other configurations give me, and would any of them be worth the money?

I pretty much want instant response on what I do, but the most intensive things I will do are DVD decryption/encryption type stuff while doing tons of multitask with things like itunes and such.


More about : selection question

a b à CPUs
August 16, 2009 7:36:57 PM

well, since you absolutely will not OC yourself
i would say the 920 w/ 20% OC
at 3.2GHz (920+20%OC) you will not see much of a difference between it and the i7-975 3.33GHz (only 133 MHz faster)
a b à CPUs
August 16, 2009 7:38:17 PM

though if you can afford to burn 4850 for the processor alone, you could go for the i7-965 with a 20% oc (4GHz)
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a b à CPUs
August 16, 2009 7:44:09 PM

Get a good cooler, PM me, Payme $20 paypal and ill tell you how to OC on the phone.
a c 309 à CPUs
a c 121 K Overclocking
August 16, 2009 7:47:49 PM

Realize that the 920, 950, and 975 are all the same chip. A 20% overclock to the 920 gets you about a 975, and that is very conservative.

Spend your funds elsewhere.
Perhaps a intel SSD for the OS.
Perhaps more than 6gb for multitasking.
a couple of 1tb hard drives for processing.
August 16, 2009 8:00:30 PM

OK so I take it the 920 at 20% is the best way to go for me based on what I am hearing. No, I dont have obscene money to do the 975 at 4.0 (I wish). Thanks for confirming my plan guys. If anyone disagrees, let me know.
a b à CPUs
August 16, 2009 9:58:17 PM

Dude, as pointed out they're all fundamentally the same chip. The 920 is so easy to clock up to 4GHZ (i.e. a 50% OC) it's daylight robbery that they're charging you $90 for a measily 20%

Seriously though, if this is a pre-built system then they'll have the CPU cooler properly mounted so you don't have to worry about frying the CPU. Either find somebody who'll clock you to at least 3.8GHz or ask the guys here and do it yourself. I know you don't want to but you're not going to break anything and that $90 can go to something else or just save it.

$90 for a measly 20% is daylight robbery.
August 16, 2009 10:10:37 PM

Ok, I know people on these forums are very pro "do it yourself" and seem to make things sound easier than they would actually be. If you assume I am a complete idiot with no computer adjusting experience, how hard and involved would it REALLY be to do this. (I have seen lots of threads with more competent people struggling in the BIOS and other things that I would just be so lost in). It does interest me to push it closer to 35% or something, but I would want NO risk of frying it or doing something that would create problems and complications. Not to sound wasteful, but 90 is a very small price for piece of mind.
August 16, 2009 10:36:28 PM

any decent i7 MB is going to come with overclocking software that will get you to around at least 3.4 - 3.6. If you are scared to go into the bios then you can use this software from inside windows and still save yourself the $90.
a b à CPUs
August 16, 2009 11:19:27 PM

Honestly, it would be almost no effort at all to overclock it yourself, assuming a decent BIOS. Do you know which motherboard will be used?

All you need to do to overclock is increase the bclk, set the voltage manually, and make sure all other clocks (RAM, QPI, etc) are running where you want them (usually as close to their rated values as possible). If you just want a simple overclock, rather than a fully maxxed out setup, it would only take 15 or 20 mins.

Here's what you would do to get an i7 920 to 3.6GHz:

1) Turn off turbo mode
2) set bclk to 180
3) set core voltage to 1.3675 (or as close as you can)
4) Set RAM to a speed as close as possible to the rated speed (likely 1333 or 1600)
5)Boot into windows
6) Stress test with something (such as Prime95)
7) If it passes (and it will, with that voltage and clock), go back to BIOS and decrease core voltage
Repeat steps 6 and 7 until it is unstable, then bump the voltage up a bit. You now have an overclock that is stable and completely safe (I'm assuming a decent cooler here).
a c 309 à CPUs
a c 121 K Overclocking
August 16, 2009 11:22:09 PM

What motherboard will this system have? Most X58 motherboards will have an option to change the BCLK(base clock) of the system from 133 to whatever. That is done in the BIOS. The 920 cpu operates at 20 x the base clock. When turbo mode kicks in, it is upped to 21. That gives a base speed of 2.66ghz(20 x 133) and 2.79(21 x 133) in turbo mode. Turbo mode is activated when the cpu is pushed, and not all cores are active. If you increase the BCLK from 133 to 160, a 20% increase, you will operate at 3.2 and with turbo boost at 3.33. I consider this a safe level since that is the speed of the 965 model. Such a modest increase can be done with no other changes to voltages or other settings, at least on a Asus P6T deluxe. The faster speed will increase the heat generated in the cpu, so a good cooler is very helpful. If the cpu gets too hot, (>70c or so) it will throttle back the multiplier to protect itself.

The cpu can be pushed even higher with aggressive cooling, and increases to voltages, but that requires more knowledge, and increases the risk of damaging something.

If you get a cpu with the newer D0 stepping, overclocking is easier, and a safe limit will be higher. Also realize that your results may vary, depending on the quality of the individual chip. Intel can not sell that many 975 units so many chips of 975 quality are sold as 950 or 920 chips. You can get lucky and get one of those, or not.

Still, even at stock speeds, the 920 is a shockingly capable cpu. Turn on the windows task manager, and observe how lightly loaded those 8 threads are. You probably will not be able to make use of anything past the free 20% easy overclock. I suggest you get the 920 without the 20% overclock, and when you feel comfortable, try increasing the BCLK a little bit at a time to see how you do.
a b à CPUs
August 16, 2009 11:27:34 PM

geofelt - I wouldn't even overclock to 965 levels if you leave the voltage on auto. My experience with the P6t deluxe is that on auto, it is rather enthusiastic with voltages for an overclock, and it will end up running far hotter on far more voltage than it really needs for that level of overclock.
August 16, 2009 11:47:57 PM

Wow geofelt, way to drop some knowledge. Thanks for that, it is exactly what I needed. I think I will end up getting the Asus P6T Delux.

When you say pushed higher needs some aggressive cooling etc., do you mean past the 20%?

Cyberpower is only offering one option on this desktop for cooling:
Asetek LCLC 240 Liquid Cooling system w/ 240MM Radiator and Dual Fans (Extreme Overclocking Performance + Extreme Silent at 20dBA)

OK, so I know it says extreme OC performance, but I wonder how "aggressive" that is exactly.

So to recap, (assuming you think over 20% is possible with this cooler) you would say getting the 20% and seeing how much I use would be good. Then experiment with furthering that on my own? I really dont mind paying 90 if it ends up that I wont even push it further than that.

Also, should I basically look at a 20% OCed 920 as being the same as just buying a 975 and running it at stock? That is what I gather, but want to make sure.

Thanks again

a c 309 à CPUs
a c 121 K Overclocking
August 16, 2009 11:49:57 PM

cjl said:
geofelt - I wouldn't even overclock to 965 levels if you leave the voltage on auto. My experience with the P6t deluxe is that on auto, it is rather enthusiastic with voltages for an overclock, and it will end up running far hotter on far more voltage than it really needs for that level of overclock.

CPU-Z shows my core voltage to be 1.240 I think that is nominal. Everything else is Auto.
The last time I checked, my ram was running at 1.5v.
The system has been absolutely stable from day one. I assumed that I did everything ok.

@cjl: I see you have 12gb.
1) What differences/benefits do you see compared to 6gb?
2) Did populating all 6 ram slots impact your overclock?
a c 309 à CPUs
a c 121 K Overclocking
August 16, 2009 11:56:11 PM

I think even the stock cooler would be OK for 20%. But I would suggest a good air cooler. Your cpu will run cooler, and the 120mm fan that is used will be much quieter. Here is a link to a review some of the best coolers:
http://www.frozencpu.com/resource/r24/Best_CPU_Cooler_P...

Differences among the top ten are minimal.

I consider liquid cooling to be in the aggressive category. I see no need to go that way unless you are an enthusiast going after record overclocks.
a b à CPUs
August 17, 2009 12:03:17 AM

geofelt said:
CPU-Z shows my core voltage to be 1.240 I think that is nominal.
Yep, that's a normal voltage for the CPU when it's under load, even when not overclocked.
August 17, 2009 12:08:19 AM

i would be curious about the 6gb vs 12gb ram question too. I am planning on starting with 6 @ 1600 and then probably upgrading to 12 very soon after.
a b à CPUs
August 17, 2009 1:09:44 AM

I noticed a difference with 12GB specifically while running some large Solidworks models. It isn't really significant for normal system responsiveness or gaming. I'd start with 6 gigs, and not worry about 12 unless you are finding that you are consistently running short on memory for certain tasks.

Oh, and it had no impact on my overclock, aside from the fact that I had to bump my QPI/DRAM voltage up just a bit.
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