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I5 750 Tcase and Tjmax, misc stuff

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June 1, 2010 6:55:26 AM

Hey!

I've got yet another issue :D . Well the overclock works fine if I set bclk to 160, 20x multiplier and adjust ram to 1280 mhz. In a nutshell, it works ok without any voltage changes

Ok, so it runs fine doing an hour test of OCCT and passes 4.5 ish hours of Prime95, peaks at 79c but stays mostly at 76c. I "thought" this was ok because of stuff I'd read about Tcase and Tjunction where RealTemp or Speedfan measure the Tjunction of each core. Tjunction apparently is 5c higher than the Tcase of the overall chip (and here is another question of is the difference 5c or 15c? So is tjmax around 77c or really 87c? or is tjmax entirely unreliable?)

So I was a bit jumpy but mid 70's seemed ok. It finished a number of tests, no errors.

I put it through Linx and it starts hitting 84c so I shut it down. 84 degrees is a bit too much, correct?

I'm cooling using an Arctic Cooling Freezer Pro Rev. 2. Installed everything months ago but overclocking now so the thermalpaste has had time to set. Should I try to reseat? And if I do reseat the heatsink, will I have to wait a while for the paste to set before I start overclocking again?
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June 1, 2010 8:34:23 AM

To be honest, it's best if you don't go above 75°C. On Intel's website the max CPU Tcase is 72.7°C, but Intel likes to play it safe sometimes, and AFAIK, the max is around 90°C before temperature throttle, so 87°C could be the max temp before it starts throttling down.

You only need to reseat it if you feel you used too much paste originally, or don't think it's mounted right. I do feel that 76°C on average max load is a bit high for a Core i5 750 chip with a mild overclock to 3.2GHz.
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a c 100 K Overclocking
June 1, 2010 2:34:40 PM

It might depend greatly on paste, but I reseated my HS multiple times one week to see if I could get better temps... from the initial temps I managed to get them maybe 1 or 2C lower by the end.

Considering you're overclocking, you've technically already voided warranties. However, OCing can be hidden so it might not matter... anyway, it's very possible the chip surface is wavy and by lapping it you could greatly reduce the temps. I actually had my temps hitting over 80C in Prime95 when I first got my PC - I don't recall if it was 160 bclk but I think it was - and then I decided to lap it and it dropped the temps by about 20C surprisingly. I know, that's odd, but my chip was bad - when I took of the HS the paste was only in contact basically down the center of it so there was large portions not touching the chip.

I can't really recommend lapping because it voids warranties. In fact if you have IPR at the store you bought the chip from it might be worthwhile to bring it in and have them check load temps... if they're too high you can get a replacement.
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June 1, 2010 8:22:49 PM

I was really surprised when I hit 75 and above with such a mild overclock as well. Uhhh, right now I'm moseying around inside and am working on redoing all the cable arrangements, they were really sloppy before. Plus I vacuumed all the dust out of the heatsink and it was loose so I had to tighten it o.O.
Haha I'm not sure I want to go into lapping now. I read up on it but I'm not ready to take that risk unless it's screwed and I can't get a replacement VVV.

I didn't buy it at a store, I got it off of Newegg....I may have to go to Intel and talk to them about their 3 year warranty

Once I finish up fixing everything up, I think I'm going to set it at stock speeds and run Linx again. Hopefully it'll be ok then and I'll go up from there. Possibly even lower voltages as well.
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June 1, 2010 10:11:24 PM

I made a note here, huge success!

Yeah, I cleaned it out, made the cables much neater, vacuumed a crap load of dust off the heatsink and tightened it down and lowered the vcore from 1.26875v to 1.12500v

And it works! Idle is even lower at 30ish c and Linx is running like a champ at 65c peak. Prime95 for an hour to double check this and I'll be good

Thanks you guys! Damn, now i wanna try oc'ing again lol
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a c 100 K Overclocking
June 1, 2010 10:27:29 PM

Dust? Yeaa that was probably the #1 issue. Dust clogs caused me to melt my old 8600GT which caused a year of not playing PC games =/ lol

Anyway, glad it's all better now! Just remember to clean that thing out every 6 months or so ;) 

EDIT: oh right and about lowering the voltage... well, it's great that it works, but working isn't the same as stable. Prime95 can take a while to find an error. On my previous MSI board I had it come up with an error after 4 hours, then upped the Vtt a notch and it errored after 7 hours, 1 more notch and it didn't error after about 11 hours so I left it. I'm currently using a diff mobo (ASUS) however and so far it's only stable for about 4 hours but in this case I have to raise Vcore since Vtt is already slightly higher than it was on the MSI board... anyway, I just want to recommend an overnight Prime95 at least 8 hours or so.
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June 2, 2010 2:57:49 AM

Oh, damn. High voltages make for hotter temps but too low and it might not provide enough power and die on you, right? I'll check on what other ppl have for a 160 bclk overclock and if it's far off, I might adjust again before Prime95'ing. It seems ok right now and passed Linx 20 passes ok but I'll double check with Prime again. How's your i5 overclocking going? I saw you had a topic for yours
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June 2, 2010 6:37:15 AM

Good thanks. Just got it stable today. This morning 1 core failed in P95 after about 3hrs but I managed to run it for 8hrs no problems this afternoon. Most settings on auto but I have 175bclk, turbo is on so it gets up to 4.2ghz. Vcore is 1.30635V and Vtt is 1.20625V. Max temp was 63C tho mostly it was right at 60C and my lowest core is always 5C less :) 
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June 9, 2010 1:01:23 AM

Whoops, forgot to get back to you. Wow.....I remember you said you left turbo on but that's pretty sweet! Yeah, I'd imagine that using such high voltages with turbo on as well would make it a bit dodgy but that sounds mostly stable. Haha, gotta love that difference in core temperatures. I know my spread was around the same, like a 65 and 64, then a 60 and 61. Still, better a slight spread than one core skyrocketing to 80c, right?

Hmm, only thing left now is to replace this old 8800gt with something a bit newer, snazzier. I'ma thinking of the gtx 470 but in good time, you know? No rush right now, not yet until some of the good upcoming games come out :D 
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June 16, 2010 12:10:45 AM

Best answer selected by deltalives.
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