NB block - CPUs are flat, but what about NB?

[RoboTech]

I have been reading a lot of posts recently on other boards about how concave some of the chipset surfaces are - specifically the nVidia NB. I just recieved my EP-8RDA+ today and mine looks pretty good - not near like some of the pics I have seen posted.

Both the North and South bridge chips in the nVidia chipset seem to run pretty hot, especially as you wind up the FSB. I'm planning to do a waterblock on the NB and put the stock (but lapped) NB HS on the SB.

I know there have been strong opinions about CPU chip flatness here with the facts to back them up. Does anyone have experience with the nVidia NB and how flat or not-flat it is? Has anyone looked at a NB under an optical flat?

Could it be that the actual chip itself is flat and it's the surrounding package that is not? Wouldn't all large ICs be flat by nature of the process? Thanks in advance for any thoughts...

[hydrogen18]

if it looks like what i think it looks like(thinking gf4 ti type package) it can be lapped. only the intel chipsets which have cores based on the package like a p3 core cannot be lapped.

[MadDogMe]

I don't know about an nF2 chipset but every nvidia GPU and most NB's I've seen are 'embedded/encapsulated' in plastic or under a copper slug (Ti's). they have all been far from flat, I lapp my GPU's and NB cores always if I'm going to overclock. I've had big improvements in mem timings after lapping a ALiMajik NB, went from fast~Ultra on the same memory, could'nt test FSB increase cause it was capped at 147...

You seriously don't need an optical flat to see the amount of iregularity, just lapp your HS then put some paste on it and see what markings are left on the NB & HS. I'd bet a pound to a penny it'll be 'edges only...

[RoboTech]

Hey MadDog,

Yeah, I'm just starting to look into this and my initial impression is that it is the surrounding package and not the chip surface itself that may be causing people problems. The plastic package moulded around the nF2 NB is definately higher, and prevents the heatsink from fully contacting the chip. The wad of OEM bubble-gum more than takes up this space...

Still, my real question is whether or not the chips themselves (GPUs and NB) are flat like a CPU or if there is some difference in the manufacturing process that makes them curved???

[MadDogMe]

It's probably not the chip in the centre, just a slug/heatspreader, is it round and made of metal?, usually nickel coloured/plated. If so it's probably a copper slug like on the Gf~Ti range. By the way the slug (if that's what it is) is usually (9 out of 10) bowed as well . The chip can usually be seen by it's 'imprint' once lapping is started, it's about 10mm x 12mm on most GPU & Chipsets I've lapped...

[WinFlex]

Lol... nice idea, but astronomical costs would be associated with milling this... plain impossible on a non EDM machine.

lol. this somehow popped up in the wrong thread... sorry... just incase you were wondering, It's supposed to be in BigBen's spiral thread

[RoboTech]

Originally posted by MadDogMe
It's probably not the chip in the centre, just a slug/heatspreader, is it round and made of metal?, usually nickel coloured/plated. If so it's probably a copper slug like on the Gf~Ti range. By the way the slug (if that's what it is) is usually (9 out of 10) bowed as well . The chip can usually be seen by it's 'imprint' once lapping is started, it's about 10mm x 12mm on most GPU & Chipsets I've lapped...

Yes, that describes the nF2 NB pretty well...

A round metal center, just over an inch in dia - looks like nickel plate with black printing on top, surrounded by a square, black plastic package. Some people have posted lapping (dry sanding) this chip until it started turning copper color - seems to fit your description well.

So if I understand correctly, the top chip surface (which is typically FLAT) is not exposed, but covered by a metal heatspreader slug and encased in a black plastic carrier - niether of which are very flat.