Considering to do extreme cooling and I like some feedback

[wutske]

I haven't decently overclocked anything since my Athlon XP 2500+ (and I totally didn't win the silicon lottery with that one 🙃), but lately I've had a lot of fun with some LGA775 CPU's. I've got some nice numbers on air, especially with the -5°c we've got lately here in Belgium, but I feel some of my cpu's can go even faster with some more extreme cooling methods (and having to wait for a cold night, then sitting in my bedroom on my bed to trying to overclock the computer that's outside on the balcony isn't exactly comfortable).

So there's a couple of options I'm considering and I'd love to get some feedback on my thought before I make a decision. FYI: I'm not looking to break any records, I'm mostly looking into this to have fun (though moving up some spots in the rankings is always a nice reward 😁)

 

Peltier (TEC)

This is probably the worst option due to how inefficient these things are. Even a CPU which runs stock at 95W needs a 200W peltier element and some decent water cooling to keep it under control. I'm also not really expecting sub-zero temperatures under load with these.

Phase change cooling (SS)

The thing I like most about SS is that they are easily reusable and I can pop it on a CPU whenever I want, no need to go buy consumables. However, I'm having a hard time finding one and shipping these from abroad seems risky to me (let alone the fact that maintenance on these things requires skills and certifications which I don't have and which are expensive to get in Belgium). Single stages go sub-zero, but it's limited, especially under load and these things usually have a certain TDP range in which they work most efficiently.

Dry ice

To be honest, this seems to me like the best way to start, it's not as extreme as LN2 but -78°c is already a pretty damn good temperature. I'm a bit worried about the costs of it in the long run. I found some stores selling dry ice, but they all seem to require you to buy a minimum of 5kg for roughly €20-€25. I also can't find any numbers online on how much dry ice you'd use in a day, but the main issue is that you must use it all in one day since dry ice is kind of gone after a day or two, so I need to plan in advance when I want it and then probably spend over an hour in the car to pick it up.

There's plenty of options for pots and accessories (thanks to this topic), which is great. Starting with DI seems kind of easy and relatively cheap to start since it doesn't require any special gear.

LN2

This is probably the most extreme (apart from helium) and is a immediately a deep dive into extreme overclocking. I'm not sure if it's the "best" to start this low. I can't seem to find stores that don't require you to get a quote for pricing but based on this topic I guess about €1/L seems to be a common price. I remember from some Youtube videos that 10-20L a day isn't uncommon, so the price is a bit similar, but I can buy a larger quantity and use it a couple of weekends (thus requiring a bit less planning compared to DI, since I don't need to order on a specific date/time and drive like an hour to get it).

Same remark when it comes to pots and accessories. Dewars can be rented but I suppose they don't come with the right fill lines so I'll have to get those too (+ some good gloves), which makes it a bit more expensive to start with.

 

So, am I seeing it the right way or am I missing some important things ?

 

 

[Leeghoofd]

Which setup do you plan to bench ? Socket775? is it 2D only or also planning some quick and dirty 3D runs?

The most cost effective to start with is Dry Ice, Indeed you need to plan as once the box is opened it evaporates quickly. A second hand pot will cost around 100-150 euros.  Some acetone, and proper insulation will give you hours of fun. 5KG is not that much depending on the things you want to do...

A single stage will set you back immediately 700-1500 euros. Depending on the build quality and the specs you are indeed limited to -60/70ish. A solid Cascade is easily 2000 -2500 Euros, temps varying between  minus 80 to minus 120°C but far better load holding capacity than a single stage. However once the setup runs and if you don't have a CB or CBB plagued setup, hours of intensive fun are possible.

Before going LN2 I would advise to do either one of the above first, LN2 in Belgium is freaking expensive, you need to have a dewar or two, torch, good K probes, temp meter,... to max things out/ Las tbut not least so much more can go wrong with LN2 as everything freezes way faster. 

 

Just give me a PM where you live, maybe we can work something out I still have pots and a modern SS

[spit051261]

Also need a good heater with LN2 on a separate power supply .

Plenty of guides kicking around.

Most people I know start off with chiller then phase and then go onto LN2.

Tried Dry ice but too much condensation for my liking.

Fasttrack is the guy to talk to about dry ice .

Edited December 26, 2022 by spit051261

[wutske]

3 hours ago, spit051261 said:

Also need a good heater with LN2 on a separate power supply .

Plenty of guides kicking around.

Most people I know start off with chiller then phase and then go onto LN2.

Tried Dry ice but too much condensation for my liking.

Fasttrack is the guy to talk to about dry ice .

I've also thought about chillers but since I don't already own a custom loop, it probably adds a lot of complexity for starting out (+ there's a lot of tubes that can also suffer from condensation). How is dry ice giving more condensation compared to LN2 ? Do you mean there's a higher risk of "liquid" water compared to LN2 where the risk of it the ice melting is smaller ? I was also considering using a heater with the dry ice to stop condensation from forming on the back of the motherboard, but from what you're saying that's not needed ?

 

3 hours ago, Leeghoofd said:

Which setup do you plan to bench ? Socket775? is it 2D only or also planning some quick and dirty 3D runs?

The most cost effective to start with is Dry Ice, Indeed you need to plan as once the box is opened it evaporates quickly. A second hand pot will cost around 100-150 euros.  Some acetone, and proper insulation will give you hours of fun. 5KG is not that much depending on the things you want to do...

A single stage will set you back immediately 700-1500 euros. Depending on the build quality and the specs you are indeed limited to -60/70ish. A solid Cascade is easily 2000 -2500 Euros, temps varying between  minus 80 to minus 120°C but far better load holding capacity than a single stage. However once the setup runs and if you don't have a CB or CBB plagued setup, hours of intensive fun are possible.

Before going LN2 I would advise to do either one of the above first, LN2 in Belgium is freaking expensive, you need to have a dewar or two, torch, good K probes, temp meter,... to max things out/ Las tbut not least so much more can go wrong with LN2 as everything freezes way faster. 

 

Just give me a PM where you live, maybe we can work something out I still have pots and a modern SS

I'll probably start out with socket 775 since that stuff is just lying around and it's expendable, though I'll probably give my 2500K a go once my new BIOSes arrive (and I manage to revive my desktop). I'm also going to start with 2D first, 3D might be something for the future since I don't have spare GPUs and older GPUs are generally more complex since they need volt mods.
I also have a couple of socket A CPUs lying around so if I find a good mobo I'll also give them a try too (I really hate that I sold my NF7s v2.0 a year ago ).

 

Okay, so for a full day of benching I should probably go for 10kg of dry ice ? That's a lot, but I guess I won't be doing this every weekend 😁.

 

-60° for a single stage seems like a lot (of cold). I checked the XS forums a lot when I was younger and I remember that the -100°c club (without any load) was pretty much exclusive for triple stage cascades, most single stages were around -30°c (but then again, that's what I remember from 15+ years ago 👨‍🦳 ). Anyhow, as expected it's probably too expensive for just having some fun. A dry ice pot ain't cheap either, but I can still re-use it if I want to play with LN2.

[macsbeach98]

Dryice is the cheapest and easiest to start with board insulation isnt too hard for -70 and no 775 chips will CB at that temp.

Sit the board on a 12mm closed cell foam sheet with the backing plate studs through the sheet no air gets to the back of the board no condensation the top of it cut close cell foam to go around the CPU socket and the bottom of your pot no air gets to the socket no condensation everyone does it different blue shop towel will be your friend too look at different guides to see how other people do it.

It isnt as hard as some make it out to be.

[wutske]

Oh that's good to know that just foam insulation is enough for DI.

There's a lot of LN2 overclockers out there so a lot can be found on LN2, but dry ice seems to be less popular so that kind of knowledge is a bit harder to find.

 

Thanks for the input 👍