why is this?

[mirko_3]

I'm relatively new to watercooling - been running this homemade system (pop can block :)) only for say 1.5 months...
anyway, it looks to me like everyone in this forum who is watercooling has load temps that are like 3-5 degrees higher that idle; I, on the other hand, have like 28 idle and 41 load... since I don't have my heater core yet, after a couple hours they get higher as the water heats up too much, but that doesn't really matter.
Why is there such a big difference between the temps?

FYI:
900 l/h pump
pop can block; it's copper, 6mm thick, lapped
only watercooling the cpu right now

[Diggrr]

You don't have a heatercore?
They are capable of shedding the heat from several cpu's, so one is a minor task for them to keep up with.

[Lumen]

Im guessing that the processor is putting out too much heat for the water just too cool off by itself. Most likely when you get a heater core you wont have this problem anymore.:)

[SemiCycle]

I agree with the other 2 guys 100%. Your ultimate goal is to move the heat from your cpu to the air as quickly as possible. The water helps to get this proccess going by removing heat quickly from the waterblock, but a heater core or some other form of a radiator is need to move the heat from the water to the air.

[JFettig]

It could also be not very good processor contact causing this... maybe try to remount the waterblock. I love to see people make these popcan blocks successfully!

[SemiCycle]

LOL, I bet you do.

What is that saying again?

"the best form of flattery is imatation"

:D

[Daemonfly]

since I don't have my heater core yet, after a couple hours they get higher as the water heats up too much, but that doesn't really matter.

This part bothers me...

At what point are you taking your temps? Most people's temps should(if they're honest) be taken after the system has been running long enough for the water temp to be stable, for both idle & load.

By the quote above, it looks like you're taking the temps at startup or early on in the process? before the water temp stabalizes?

- Edit - miss read part of the post, but the above still applies.


Like already mentioned, add a radiator or heatercore to dissapate the heat that the water is removing from the CPU these are an integral part of a WC system. Without anything to dissapate the heat, it will just mostly stay in the water and will keep rising with the CPU heat until either the CPU burns or throttles (P4) (probably happen first) or you reach a maximum heat point.

[mirko_3]

Ok, let's clear some things up:
if after startup my idle is 28 and load 40, after a whole day that the computer has been on, idle is 30 and load 43... that's because I have 2 80mm fans mounted on my 'reservoir' (I actually stole it from my three year old brother...it has a duck painted on it...:))
I think I'll lap the waterblock better, beacuse the missing heatercore shouldn't really be a problem: after all, load temp gets from 30 to 40 in like 3 minutes of running Folding@home or playing UT2003, then slowly gets to 43 as the water heats up. But it those 3 minuter, the water doesn't really have time to get warm, so the problem, IMO, shouldn't be there.

BTW, I did this block with my friend (he recently registered to forums as -rasta- or something), and I've noticed on thing: we both are in need of a heater core right now, but I have a 1.5 liter reservoir, his is 6 liters. His temps are like 5-7 degrees lower :( but that's to be expected. If he puts ice (like he often does) in the reservoir, they drop to 15 idle... oh well, I don't really have space for something that big.
Also, I have to keep refilling my reservoir every 2 days or so, as water evaporates real quickly!

-edit-
I forgot to mention, I lapped it real quickly the first time - like 1 minute with 350 grit and 30 seconds with 600 grit... I was in a hurry to turn the computer on...:)

Also, I'm using some generic thermal paste (my friend uses artic silver 3) so my temps could be somewhat better... this was just to let you know that the pop can block rocks!

[NeoMoses]

sounds like it could be a problem with the block. Try taking it off and lapping it. More important than it having a mirror finish is that it be flat. You can check this with a good machinist's ruler (most metal rulers will work). Once you are done lapping, hold the ruler against the bottom of the block. You shouldn't be able to see any light between the ruler and the block. If you can, lap it again, but on a better surface.

[NeoMoses]

also, how thick is the baseplate? Is it copper?

[Lumen]

Ok, ill say it again, YOUR PROBLEM WILL BE SOLVED IF YOU GET A HEATER CORE MOST LIKELY!

[mirko_3]

no need to get mad :) and it's not really a problem... not big one anyway...
the copper base is 6mm thick, I had a 5mm thick one earlier and my temps were like 5 degrees better, but it was also lapped better...
I guess I'll just have to lap it;
thanks guys

[NeoMoses]

Originally posted by mirko_3
...Also, I have to keep refilling my reservoir every 2 days or so, as water evaporates real quickly!...


If he's losing that much water to evaporation, he may not benefit that much from a heatercore. It sounds like he's (maybe inadvertantly) running a bong.

[mirko_3]

sorry, this may be a stupid question, but I'm not english: what's a bong? :)
Anyway, I didn't mean I have to refill my reservoir every 2 days completely, but the water level drops like 10cm every day (if I keep the pc on all day, which I often do); the reservoir is about 20x20 cm...
I think that the 2 80mm fans on top of it help evaporation a whole lot... oh, and the pump is in the reservoir...(do pumps produce a lot of heat or does it vary a lot between pumps?)

[Volenti]

you're already running an inificent form of "bong" (evaporative) cooling, you could use a larger res, with more surface area, would probably keep the water down to a similar temp that a heater core would, course you would still have to top up the water every now and then.