How do i test to see if my CPU is concave?

[phi1]

Hey all, I am getting very bad temps with my CPU at stock 56 load with TAT.. 30/45 idle.. I am thinking the cpu could be concave? I have a zalman 9500. If its concave what are my options that i can do? whats the best air cooler. Because i know the CPU overclocks as i have had it at 2.93ghz had plenty left. I had to stop and go back to stocks because off the temps..

Many thanks Phil

 

[Ross1234]

if by concave you mean not flat then put something flat against it

 

[Jokester]

Have a look here:-

http://forums.overclockers.co.uk/showthread.php?t=17638510&highlight=optically+flat

 

[YorkshirePadd26]

Hey all, I am getting very bad temps with my CPU at stock 56 load with TAT.. 30/45 idle.. I am thinking the cpu could be concave? I have a zalman 9500. If its concave what are my options that i can do? whats the best air cooler. Because i know the CPU overclocks as i have had it at 2.93ghz had plenty left. I had to stop and go back to stocks because off the temps..

Many thanks Phil

Ask a very small person if they can skate it !

 

[IAmATeaf]

Best thing to do is put a straight blade against the top and then move the blade round the top say in 45 degree angles and then check how much light you see.

 

[Bubo]

Using a permanent marker draw a cross on the heat spreader from corner to corner. Place a sheet of fine grit wet and dry on a flat surafce and go as if you were going to lap the cpu, only give it virtually no pressure. If the cross remains unscratched in the centre of the spreader its concave. Doing this obviously puts some scratches on the edges so only do if you're not bothered about that.

 

[IAmATeaf]

Using a permanent marker draw a cross on the heat spreader from corner to corner. Place a sheet of fine grit wet and dry on a flat surafce and go as if you were going to lap the cpu, only give it virtually no pressure. If the cross remains unscratched in the centre of the spreader its concave. Doing this obviously puts some scratches on the edges so only do if you're not bothered about that.

I prefer my method no offence

The above assumes that the bottom of the HSF is flat so if it aint then it's going to taint the results.

 

[Bubo]

If you think your hsf isn't flat then you are going to want to use the pen cross method anyway, cos that will tell you automatically when it becomes flat with no messing about with razor blades.

 

[phi1]

ok, Its rather concave! ahh.. Whats the risks and benifits in my lapping?

 

[jongeeone]

Risks : Voiding warrenty

Other Hand : Very better temps.

 

[drunkenmaster]

risks;- voiding warranty, killing cpu.

benefits, negliable performance increase in benchmarks with slightly increased overclock, possibly still bad temps if room and case are warm without great airflow and a poor heatsink. 1-2% increase in game framerate even if you get an extra 300-400Mhz out of the chip.


56C isn't that hot to be honest, what vcore were you at, still default? as long as its stable theres no real issue with temps, also whacking up the speed doesn't increase temps all that much, if you got another 200Mhz out of it on same voltage temps would barely increase.

also a better sink, probo the thermalright 120ultra plus, or maybe the 140mm version they are bringing out(only seen one review as of yet but its only compared to stock sink).

 

[Darg]

I lapped mine the other day. Very easy to do. Takes 15 minutes if you do it right.

Just get some 400,800 and 1200 grit sandpaper from a car shop. Start off with 400 and work up. Sand it in slow circles rotating the chip 90 degrees every 30 circles or so. Keep going until you get down to the copper then check with the razor again.

Perform this on a flat surface. Glass is good. I used a glass chopping board which was perfect. If you still have the black safety cover for the pin side then put that on so that no particles get on that side. clean it off every 60 circles or so with a clean cloth or cotton tip.

 

[phi1]

Did it bring your temps down a lot?

 

[IAmATeaf]

Did it bring your temps down a lot?

Nah, but his nails are now perfect

For a severely concave CPU I've heard reports of people getting anywhere up to a 5 degree improvement but the biggest gain by far seems to overclocking stability when both cores run at roughly the same temps.

 

[g00dsh0t]

Nah, but his nails are now perfect

LOL

 

[phi1]

I lapped mine the other day. Very easy to do. Takes 15 minutes if you do it right.

Just get some 400,800 and 1200 grit sandpaper from a car shop. Start off with 400 and work up. Sand it in slow circles rotating the chip 90 degrees every 30 circles or so. Keep going until you get down to the copper then check with the razor again.

Perform this on a flat surface. Glass is good. I used a glass chopping board which was perfect. If you still have the black safety cover for the pin side then put that on so that no particles get on that side. clean it off every 60 circles or so with a clean cloth or cotton tip.

I am using a zalman 9500! :S

 

[marscay]

my chip was pretty flat but i still gained a good 5-7c under load after lapping.

decide whether you can live with no warranty and go for it if that's a yes.

 

[phi1]

umm i just had it out, Its not even that much concave, Just a tiny bit. I could see a tiny bit off light with my credit card next to it.. I decided to stick on my stock cooler and it seem to do a better job??? Whats going on.. Its still hot 32/32 in coretemp and 20/20 in speedfan.. Thats idle.. Do you think its worth me lapping it then?

Phil

 

[phi1]

here is a pic showing what mean