Ultimate 4U 500mm Chassis - Who is interested?

[ItsAllInMyHead]

One of these specs is very wrong.
250mm is only 25% longer than 200mm.
If 5U x 200mm does 0.28 C/W, then no way will 5U x 250mm do 0.19 C/W

A more accurate figure assuming 0.28 C/W for 200mm is accurate would be around 0.22 C/W for 250mm

Another problem with these specs, is no rise above ambient data is stated. Heatsinks dissipate heat more efficiently the hotter they get, that is a heatsink could have measured properties of 0.28 C/W for a 30C rise above ambient, but for a 25C rise above ambient the specs might be 0.3 C/W.

I don't know. I just took them from the DIYA site. However, from the documentation Gianluca provided, the construction of I suppose what I'd call the "fin profile" is different between the sinks that we would typically associate with a 4U 400 (2 pieces of 165 x 200) and the 5U 500 (2 pieces of 210 x 250). So, not only are the overall dimensions different, but the 210 x 250 sinks have "more cross sectional mass" in the fins. That could contribute. Perhaps your assumption was based on the belief that the only difference was in the dimensions. I am not refuting any published data, I am only looking for a bit of clarification, which can help me to make a purchasing decision.

See Table 2, Figure 2, Figure 3, and Table 3. If I have this incorrect, please someone let me know. Learning here, and I truly appreciate the patience.

Here is the original thermal dissipation documentation from the department of engineering at the university of Bologna, which is the source of the published figures. You are welcome to have it translated.

Hope this can help you guys out!

Thank you!!! I am stumbling through it.

This is correct.

Thanks! But all that may be moot if the fin profile is different. Will the sinks be two piece per side or one? It was noted earlier that they will likely be two pieces, but in your summary above, it shows a combined dimension. One piece per side will be phenomenal for me, but I can work with a 2-piece design.

Edited for clarity (hopefully) and misspellings

 

[Gianluca]

It's going to be 2 heatsinks per side so 4 for each chassis, just like the 5U 500

 

[ItsAllInMyHead]

Thank you!

If it's okay to ask directly to the source...

Did I interpret the data properly in the document you linked? Specifically, are the fins for the 250 x 210 heatsinks slightly thicker toward the tips than those for the 165 x 200? Dimension S8 in the Table and Figures 3.

Two quick follow-ups if that is accurate. My calipers are not fantastic. I measured ~1.5mm at the tips for my 200 x 210 heatsinks for my 5U 400 chassis. Is that correct?

Also, more specifically, if the fin profiles are in-fact different, would the fins for this GB chassis have the "thicker" fins similar to the 5U 500 chassis heatsinks or the "thinner" fins similar to the 4U 400 chassis heatsinks. It may be splitting hairs, but if I can get the vast majority of the dissipation performance in the shorter chassis, that's what I'd prefer, but I'm prepared to "Go big or go home" if the thermal performance is markedly better.

Once again, apologies if I have interpreted anything incorrectly or if this is OT. My personal decision is between these or 5U 500s. Others may be in a similar situation.

Edited to correct the 4U and 5U heatsink dimensions referencing thickness at the tips. 1.0 vs. 1.5mm.

 

[2 picoDumbs]

Thickness only improves heat spreading.
The more important spec is the surface area and the geometry of the heatsink itself.

 

[2 picoDumbs]

My personal decision is between these or 5U 500s. Others may be in a similar situation.

The 5U x 500 chassis is likely to be around 12% to 15% better thermally than the 4U chassis.

 

[ItsAllInMyHead]

Beautiful, thank you!

 

[2 picoDumbs]

Pico's Toxic Masculinity Chassis - Definite + Possible List

4U x 500mm Toxic Masculinity Chassis

x10 310 Euro
x25 250 Euro

Definite List
Pico x 1 (maybe 2 if required to get to 25)
Gary S x 1 (maybe 2 if required to get to 25)
pwagner x 1 (maybe 2 if required to get to 25)
Hey Bill x 1 (maybe 2 if required to get to 25)
Super_BQ x 1 (maybe 2 if required to get to 25)
TungstenAudio x 1
Subbu k x 1
hifibluedevil x 1
BrianGasberg x 1

Possible List
Blk Dynamite x 1


Anyone I have missed please add your name to the list.

 

[2 picoDumbs]

Ok, I’d just need price before I can commit to a group buy. I’d definitely be interested in the form factor, but whether I can swing it now or later is tbd.

Should I add your name to the list?

 

[HeyBill]

Is it time yet?

 

[2 picoDumbs]

Still need more people to confirm they are interested to get to 25 cases or we accept the higher price per chassis.

 

[pwagner]

Not sure the rules allow this, but if so, could you post in other forums (solid state, group buys, parts) to raise more interest?

 

[Cal Weldon]

No, rule #5 covers this.
Thank you.

 

[mirlo]

I'd like to get in for two if we get to 25.
But I don't want to buy for the 10–quantity price.

 

[mirlo]

I do want steel baseplates and rear handles.

— Eric

I'd like to get in for two if we get to 25.

 

[gary s]

My thoughts as well, 10 off price is way too expensive with freight cost landed here in Australia, 25 off price might be OK. but I doubt that qty will be achieved. I am looking at other options as I see this dragging on for a while, thanks for your efforts pico by the way.

You can take me off the list for 10 off qty.

 

[2 picoDumbs]

I'd like to get in for two if we get to 25.
But I don't want to buy for the 10–quantity price.

Now wer're talking.
Bloody legend.

 

[2 picoDumbs]

You can take me off the list for 10 off qty.

Just hang in there a little longer.
I think we could get there.

The Christmas season could help us get the few extra we need.

 

[2 picoDumbs]

4U x 500mm Toxic Masculinity Chassis

x10 310 Euro
x25 250 Euro

Definite List
Pico x 1 (maybe 2 if required to get to 25)
Gary S x 1 (maybe 2 if required to get to 25)
pwagner x 1 (maybe 2 if required to get to 25)
Hey Bill x 1 (maybe 2 if required to get to 25)
Super_BQ x 1 (maybe 2 if required to get to 25)
Mirio x 1 (maybe 2 if required to get to 25)
TungstenAudio x 1
Subbu k x 1
hifibluedevil x 1
BrianGasberg x 1

Possible List
Blk Dynamite x 1


Anyone I have missed please add your name to the list.

 

[2 picoDumbs]

Essentially we need 5 more people, and it's game on.

Come on people it's Christmas you deserve to buy either yourself or a family member an awesome gift.

 

[2 picoDumbs]

I think Jason needs some more toxic masculinity in his life.

Come on Jason you know you need one of these amp cases.