The anatomy of a 'bow'.

nikhsub1 · 05-03-2007, 02:04 PM

Seems many are confused as to the whole 'bowing' sensation going round the town. Back in the day, before IHS's (or when they were easy to remove) we wanted bases flat as could be so to have the best contact with the silicon. A few months ago it is discovered that making a block convex can (and does) have a good impact on performance with IHS based CPU's. I won't go into the why's of it all, it should be pretty obvious though. Anyhow, Swiftech has started shipping fatter o-rings with their Apogee blocks, not installed but as an addition so the end user can install it and bow his base. I have verified that on a 6600 the bowed base is ~ 4.5C better than the non bowed base. Not to confuse here, the bases themselves are the SAME, it is the O-RING which will bow the base. Here is a pic of the bowed base, note the GAP between the base and the top, especially in the center between the screws that hold the block together:

One thing worth mentioning here is that once a base is bowed, it must remain this way for good - you can NOT revert it back to 'flat' as it will (the base) look sort of like a fun house mirror

.

I must confess I tinker around with stuff, this is why I STILL haven't posted my testing results yet, I'm still NOT done, sigh. Anyhow, in my tinkering I discovered that I bowed the Fuzion. Yes that is right, the FUZION. I was working (well testing really) with the nozzles and the performance was NOT there, not like when I made my CRUDE nozzle. So I thought maybe water was not flowing all through the nozzle, but perhaps out between the top and mid plate and bypassing the base altogether. I know, sounds crazy so in an attempt to PREVENT this, I took an o-ring from an EK barb and placed it between the top and middle plate like so: (sorry for the crap focus, I need to pwn my camera)

Well doing this had unexpected results! The base was not bowed like the apogee base, it is more bowed from the center, not the outside. You see, the o-ring forces the mid plate center to push the center of the base out. The cool thing is that now I'm experimenting with different size o-rings. For those of you that will rush out and try this, the EK o-ring is as BIG as I would go, a tiny bit smaller in thickness would be better IMO. The EK oring makes the base a bit 'dome-ish'. Does it perform better than stock? Yes it does, not as dramatically as the Apogee, but it does. It is a bit trickier to mount too as it has more of a point than a bowed apogee, at least with the EK barb o-ring.

Perhaps these photos will show what I mean, again sorry for the blur.

Here we have a FLAT base just removed (MP-05 LE):

Even with the blur you will note how the paste is pretty even (don't mind there corners where there is no paste).

Next up is the bowed Fuzion look at the paste, note the center where there is very LIGHT paste, this is where most contact is being made (most pressure I should say)

Next up are 3 bowed Apogee mounts, note the STRIP you see, this is the point of most pressure:

A very important aspect of using a bowed based block are the mounts. YOu will have a larger deviation from mount to mount as you are not mating 2 flat surfaces... the Apogee's bow is a bit more forgiving in this regard - at least so far as I haven't had much time to play with different thicknesses of o-rings and the fuzion yet. Bottom line is if you are after best possible temps - use a bowed base and mount several times so you can get a baseline of where your mounts are, you will get a feel for good and bad.

I hope at least this clears up some confusion with bowed vs. flat. AS you know I have NOT released any test data yet, much to the dismay of many but I will say this, the Apogee's and the Fuzion are the 3 best blocks there are - the Storm and the MP-05 LE SP can NOT compete on IHS cpu's, it is just a fact. I am not going to recommend which block to people, right NOW there are only 3 to consider, the Apogee GT (bowed), the Apogee GTX (bowed) and the Fuzion. You can't go wrong with any of these and the performance difference is quite small anyway. I soon hope to have official numbers, thoughts, concerns and ramblings.

Jupiler · 05-03-2007, 02:14 PM

Very interesting.

Regarding the Fuzion :

What was the temp difference between the stock base and bowed base (with the EK O-ring)?

nikhsub1 · 05-03-2007, 02:18 PM

Quote:

Originally Posted by Jupiler

What was the temp difference between the stock base and bowed base (with the EK O-ring)?

I'll not go into that here... I don't have all the data anyways yet.

[cTx] Nooc · 05-03-2007, 02:32 PM

great post

this should be in the FAQ somewhere

SparkyJJO · 05-03-2007, 02:34 PM

I ordered the fuzion and am running a naked opteron 165. Because it is naked I'm assuming there would be no point in bowing it right?

SNiiPE_DoGG · 05-03-2007, 04:04 PM

Sticky! please, I am really glad you posted this, because now i can use a bowed fuzion when i get it. I'll also order a bunch of different brbs to experiment with the bow amount. it looks like the one nik has is actually a bit too bowed.

question, how does bowing work with a lapped IHS?

Darkatom · 05-03-2007, 04:14 PM

Quote:

Originally Posted by SparkyJJO

I ordered the fuzion and am running a naked opteron 165. Because it is naked I'm assuming there would be no point in bowing it right?

So, no bow for any of the apogees makes the fuzion a better performer ?

serialk11r · 05-03-2007, 04:15 PM

Does the Fuzion not have an already convex base?

Petra · 05-03-2007, 04:35 PM

Quote:

Originally Posted by serialk11r

Does the Fuzion not have an already convex base?

It does... the o-ring-turned-spacer causes the midplate to push the base out further, though.

serialk11r · 05-03-2007, 04:48 PM

Quote:

Originally Posted by Petra

It does... the o-ring-turned-spacer causes the midplate to push the base out further, though.

Sorry that was in response to Sparky's post.

newls1 · 05-03-2007, 05:11 PM

Ok, but what if the CPU was lapped 100% flat, and the Base of the waterblock (fuZion) is lapped 100% flat? Since we now have 2 100% flat surfaces, would you want to introduce a "BOW"???

serialk11r · 05-03-2007, 05:21 PM

Quote:

Originally Posted by newls1

Ok, but what if the CPU was lapped 100% flat, and the Base of the waterblock (fuZion) is lapped 100% flat? Since we now have 2 100% flat surfaces, would you want to introduce a "BOW"???

There are no 100% flat surfaces, and when you mount the block onto the board...who knows what could happen to the base.

SparkyJJO · 05-03-2007, 05:36 PM

Quote:

Originally Posted by serialk11r

Does the Fuzion not have an already convex base?

That's true, I forgot about that. IIRC it is a slight convex shape but convex nonetheless.

newls1 · 05-03-2007, 05:42 PM

Quote:

Originally Posted by serialk11r

There are no 100% flat surfaces, and when you mount the block onto the board...who knows what could happen to the base.

So then why do we lap our CPU's, Heatsinks, waterblocks? So even when I lap my CPU on a piece of thick solid glass (very flat surface) down to 1200grit, my CPU still isn't flat?

Darkatom · 05-03-2007, 05:43 PM

How much of a difference is there exactly between a fuzion and a bowed GTX ?

SparkyJJO · 05-03-2007, 05:46 PM

Quote:

Originally Posted by newls1

So then why do we lap our CPU's, Heatsinks, waterblocks? So even when I lap my CPU on a piece of thick solid glass (very flat surface) down to 1200grit, my CPU still isn't flat?

It is never going to be perfectly flat. But the fact is, after you've lapped your CPU, it is much flatter than it used to be.

SNiiPE_DoGG · 05-03-2007, 05:53 PM

Quote:

Originally Posted by SparkyJJO

It is never going to be perfectly flat. But the fact is, after you've lapped your CPU, it is much flatter than it used to be.

diamond bladed mill lapping !!! (maybe those could get it flat :P)

m411b · 05-03-2007, 05:53 PM

Quote:

Originally Posted by Darkatom

How much of a difference is there exactly between a fuzion and a bowed GTX ?

I want to know too.

serialk11r · 05-03-2007, 05:55 PM

Quote:

Originally Posted by [XC] M411b

I want to know too.

Depends on flow...and heatload

p8ntslinger676 · 05-03-2007, 06:35 PM

its a pretty simple concept and i have known about it for a while, but where do i buy the o-ring?

nikhsub1 · 05-03-2007, 06:37 PM

Alex, me thinks you might have a run on EK barb o-rings

nikhsub1 · 05-03-2007, 06:38 PM

Quote:

Originally Posted by Darkatom

How much of a difference is there exactly between a fuzion and a bowed GTX ?

This question can NOT be answered as it depends.

SNiiPE_DoGG · 05-03-2007, 06:41 PM

nik, you said the EK was a little too thick with lot of bow, do you know an o-ring that is a little thinner that will reduce the bow a bit?

nikhsub1 · 05-03-2007, 06:53 PM

Quote:

Originally Posted by SNiiPE_DoGG

nik, you said the EK was a little too thick with lot of bow, do you know an o-ring that is a little thinner that will reduce the bow a bit?

No I don't have calipers to properly measure the thickness of the EK o-ring... perhaps Alex could help us out here? I'm thinking that a FLAT rubber gasket may be better than a round o-ring - perhaps it will spread the bow a bit better I just don't know yet - I've only used the EK oring and it is as large as I would go but it is useable. Once you do it though, it is a one way street.

m411b · 05-03-2007, 07:03 PM

Quote:

Originally Posted by nikhsub1

No I don't have calipers to properly measure the thickness of the EK o-ring... perhaps Alex could help us out here? I'm thinking that a FLAT rubber gasket may be better than a round o-ring - perhaps it will spread the bow a bit better I just don't know yet - I've only used the EK oring and it is as large as I would go but it is useable. Once you do it though, it is a one way street.

So, no matter the block, if you bow it, you cannot go back?