Core i7 Overclocking by Batch #

[Sniper]

Nice results patty

Sniper, your chip is borked mate, I think you should just send it to me so I can fix it up for you!!

Your Vcore is excellent, I really want a W3520!!

Sure mate

If you can find a W3540 3845B010, I think they are the best I'v seen. But all W3520 week 45-48 has a good chance of beeing a good chip (and alot of the 920 from same weeks). But there isnt much point in having a good chip unless you have watercooling, the heat output past 4.3 isnt easy to handle with air.

[rge]

4.5Ghz prime stable (3847B005), 23.4C ambients, 28.1C water temp, 1.39vcore load cpuz, 1.34qpi/vtt. Dram 1.64, rest volts at stock (not auto). Removed about 15C off load temps over past months by upgrading fans, wb, pump/top, 2x360rads instead 1, reversed fans so intake cooler external air through rads, balanced airflow, and lastly indigo extreme tim, now loads at 74C max instead of near 90C.



pic of same screen with fluke showing rad intake ambients

[Sniper]

Thats a beutiful chip, and a nice wc setup rge. I'v only got a weak laing dcc stolen from an old Corsair wc kit, maybe I should consider getting a more powerful one.

Didnt think this 3845A935 would do 4.5, it does get hot (20.5 rad intake ambient).

[rge]

You have a couple of nice xeons sniper, both need little less vcore than mine, and yeah they do seem hot, though hard to tell between different setups.

I just noticed I get 56.8 gflops at 4.5, your xeon must have little faster cache?, or memory faster, or UC.

[Sniper]

The 3848A352 runs cooler than this one (testing later by how much). Gflops depends on version of LinX, mem size used, mem speed etc. Dont think uncore gives much, but not sure.
Priming 8+ hours usually requires more vcore than 30 min of LinX.

[Sam_oslo]

3848A352 is running with OK temp up to 4.3GHZ(205x21) 1.28v on air, but it would need water for anything over that to run "cool and quiet" for 24/7, at least on my setup.

[Sniper]

Sam, you should really consider getting a wc setup, I'm sure your chip could get really high mhz.

[Kylzer]

I cant get anything over 215 blk (4.3ghz) stable anyone wana help me with bios settings

[Sam_oslo]

215 is my BCLK-wall with x20 too. It would prime up to BCLK220 with x19, but and my double-GPU (GTX 295) would need further tweaks to run stable for anything over BCLK215, anyways.

Sam, you should really consider getting a wc setup, I'm sure your chip could get really high mhz.

I know, and i should get WC long time ago. But don't tempt me.

[Sniper]

This is the the 3848A352 at 4.5. Needed one notch up on vcore in bios (same in cpuz), and 1.34v vtt instead of 1.32v used on the 935 (weaker uncore on the 352).

[DavyBoy]

Sure mate

If you can find a W3540 3845B010, I think they are the best I'v seen. But all W3520 week 45-48 has a good chance of beeing a good chip (and alot of the 920 from same weeks). But there isnt much point in having a good chip unless you have watercooling, the heat output past 4.3 isnt easy to handle with air.

I can't find anywhere at all here in the UK that sells Bloomfield Xeons, just Gainestown's..

If I could find them I wouldn't have bought another 920..

As for watercooling, I am in the process building my first loop, I was going to set it all up in my current case, but it was gonna be to much hassle, so I have decided to get a TJ07 instead.

Will be ordering it this week, and I also need to get my CPU block as well, then that will be me ready to get my CPU and GPU under water.

I am kinda scared though, as I have never used watercooling before, and I am worried incase I screw it up!!

Though I have been reading up about it for the last couple of months, and asking people lots of questions to, so I am hoping that everything goes smoothly.

[Zaxis01]

I just did a little test. not sure how accurate it is though but, i overclocked my core i7 940 and it seems the max bclk i can reach with this chip is 210 and the max frequency multi is x23 and 23x210 = 4830.
And from reading through overclocking forums it seems the max bclk of the core i7 920's is 230 and with a max multi of x21 = 4830.

So is there any real difference here besides the price?

[DavyBoy]

I just did a little test. not sure how accurate it is though but, i overclocked my core i7 940 and it seems the max bclk i can reach with this chip is 210 and the max frequency multi is x23 and 23x210 = 4830.
And from reading through overclocking forums it seems the max bclk of the core i7 920's is 230 and with a max multi of x21 = 4830.

So is there any real difference here besides the price?

I wouldn't say that it a very accurate test mate..

A D0 stepping 920 will clock a lot higher than a 940, Did you get 210 Bclk with your multi at 23 on the 940, or was this just the max Bclk you got when lowering the CPU multi?

It also depends on which motherboard you have as to high high the Bclk will go, there are a lot of mobos that have a 222 Bclk wall, and require a PCIe hardmod in order to go higher.

[zalbard]

I just did a little test. not sure how accurate it is though but, i overclocked my core i7 940 and it seems the max bclk i can reach with this chip is 210 and the max frequency multi is x23 and 23x210 = 4830.
And from reading through overclocking forums it seems the max bclk of the core i7 920's is 230 and with a max multi of x21 = 4830.

So is there any real difference here besides the price?

There is no reason to go for 940 unless you use subzero cooling.

[DavyBoy]

There is no reason to go for 940 unless you use subzero cooling.

Even if you were using sub-zero cooling, I still don't see any point in buying a 940 now, the 950 would be a much better option imo.

Someone let a 940 go on OcUK members market the other day for £180..

There are even some on the bay for £200 as well, imo it would be pretty pointless buying one of these chips now.

[tdream]

Just got a 3919A648. Hope it turns out to be a good clocker.

[koksy]

Just got a 3919A648. Hope it turns out to be a good clocker.

close to mine 3919A645. Haven't really done anything extreme yet, but no problems at 3GHz so far :P Planning on clocking it to 3.6 during this weekend.

[CryptiK]

I have a 3919A643 - its does 4.2 GHz @ 1.360v / 1.39 Vtt (Linx max mem / Prime stable).

[JonnyG]

I picked up a 3910A773. Any news on this one? Not seen one of these listed yet. The 39's seem very hit and miss. I really have fingers crossed cause i tend to always get bad clocking chips and have to buy several to even get an okish one. Still, got the mobo and ram at a steal price.

[Zaxis01]

I have my vcore set at 1.040 in BIOS and when i run anything at load it scales down to a lower voltage.
Does anyone know why this is?

[Chicken Patty]

thats because of vdroop if i'm not mistaken. I haven't read this article, but should explain it. Hopefully. Best thing would be for someone to put it in their own words. I know it is that you get lower load voltage, but I don't know why it happens, so I'll someone else do the explaining


http://www.thetechrepository.com/showthread.php?t=126

[Zaxis01]

Doesn't vdroop work the other way around by lowering vcore when idle and increasing it at load?

[imo]

[rge]

Doesn't vdroop work the other way around by lowering vcore when idle and increasing it at load?

Chicken Patty has it correct. It is about protecting the chip from overshoots, not your common sense approach of giving the chip more juice when needed.

Typically you set a vcore in bios. And if that bios is following intel specs that is the maximum voltage the cpu will see, even during overshoots/spikes.
So you set vcore to 1.1. Idle is then 1.07 that is Vdrop or Voffset the first protection from overshoots at low load, in this example of .03v. At higher load get higher overshoots, so at full load vcore is reduced more to say 1.04, since from full load overshoot is .06, so again max volts cpu sees is what you set in bios 1.1.

You can use LLC enabled on GB board or whatever called on asus boards to circumvent vdrop/vdroop. The overshoots are the same. For example Asus board with vdroop/drop disabled. Set vcore at 1.1 in bios. You may get 1.1 at low loads with overshoots to 1.13, at high loads like prime you get overshoots to 1.16.

I am just making the voltages up for explanation purposes...

[Chicken Patty]

Thanks RGE, here is an example. My EVGA board has vdroop control. I have it disabled. Somehow disabled means no vdroop, i'd thought it'll be the other way around.

Well these are stable crunching settings, vcore might be higher than needed, but haven't bothered to lower it.

This is no vdroop, vdroop will be the other way around, it lowers under load.

Idle - 1.305v

Load - 1.341v