1U P4 Systems

alvin at Mail.Linux-Consulting.com alvin at Mail.Linux-Consulting.com
Mon May 21 18:39:42 PDT 2001

hi bari... 

you're right that it;d be better to design ones own
motherboard/powersupply/1u chassis....

problem is i think most people dont have the time or
the enginnering staff to do so... and that itd be
cheaper to buy off the shelf parts...
	( or so goes the theory/assumption

most 1U chassis designs and atx motherboards fail miserably on 
dual power supply issues and hot swapp issues...
	- basically not fixable...

adding an extra extrusion to the 1U box would make it
into an equivalent 2U server... and those generic 2U chassis are cheaper
than starting with a 1U ... so there'd be no point to creating
the extrusions/extensions for the 1U to solve the
cpu heatsink problem..

the crusoe cpu is a low wattage device to begin with so
having 24 of um in the space of 3u chassis is a good idea...

the motherboard schematics etc is freely available to those that
want to build a crusoe based systems

when the proper fans and chassis designed is used.. i dont see any
problems with cooling the intel cpu....

have fun

On Mon, 21 May 2001, Bari Ari wrote:

> alvin at Mail.Linux-Consulting.com wrote:
> > hi josip..
> > you are right in your concerns...
> > 
> > teh itty-bitty 40mm fans are barely enough to keep the 
> > 1U chassis cool....even for a P3....amd and p4 requires
> > lots more cooling capacity...
> > 
> > amd athlon/duran require 250W power supply ??...
> > Intel P3 system can get away with 150W power supply...
> > 
> > larger cases ( deeper ) does NOT provide any cooling
> > improvements... you have to move the air around... and
> > the problem is the atx connectors in the back prevents
> > air flow.... front to back...or side to side is okay too
> > 
> > all of this is in 1U cases...
> > 
> > we have lateral/squirl cage fans that we are considering
> > for our next generation P4 based 1U chassis ... 
> > 
> For one P4 on an off the shelf ATX motherboard in a 1U why not just 
> replace the top of the enclosure with an aluminum extrusion with a nice 
> profile for convection cooling tied to the CPU case? There is easily 
> enough area in a 19" rack foorprint to cool off the 86W/per cpu for a 
> few P4s.
> > 
> > On Mon, 21 May 2001, Josip Loncaric wrote:
> > 
> > 
> >> Steve Gaudet wrote:
> >> 
> >>> Based on the current P4 die won't see the P4 in anything smaller than a 2u.
> >> 
> >> Except for the P4/1.4 1U RackSaver link posted by Tim...  However,
> >> cooling a 1U case concerns me.  The RackSaver RS-1100 claims to have 6
> >> small case fans (> 40 cfm total), and a 250W ATX12V power supply.  I
> >> understand the need to be space efficient, but I'd feel more confident
> >> about cooling with larger cases..
> We're designing very dense 8-16 CPUs per 1U clusters now. You can't do 
> this with off the shelf ATX motherboards and low profile ATX power 
> supplies and rely on a few weenie 1" fans for forced air cooling. There 
> are a few small footprint ATX dual Socket 370 boards that will get you 4 
> CPUs per 1U but they aren't cooled well since they are designed for a 
> typical desktop enclosure with high profile heatsink/fan combinations 
> and not a low profile 1U enclosure.
> If you look at some of the latest dense servers like the Crusoe based 
> systems with 24 CPUs per 3U announced recently, they use convection and 
> forced air cooling since they have relatively low powered (heat & 
> For dense clusters with high wattage/high performance CPUs like the P4 
> you need to move the heat from the surface of the hottest components 
> like the CPUs, chipsets and power supply mosfets by conduction out of 
> the enclosure and then rely on forced air and convection cooling for the 
> remainder of the components. If you need to get things cooler (in case 
> you're cluster is going into a very warm climate) you can also add 
> forced AC since the cost of a small AC unit and some sheet metal is less 
> than the cost of 1 CPU. Mainboard and power supply design for cramming 
> multiple CPUs and chipsets in a 1U board is pretty cut and dry. IMHO 
> you're better off building your own boards and power supplies than 
> trying to kludge up dense systems with components designed for the 
> desktop market.
> Does P4 with Rambus really make sense for clustering since SMP with 
> Athlon4 or ULV PIII with DDR is lower priced and produce far less heat 
> along with the high MFLOPS? SMP with IA-64 will also be available soon 
> to add to the choices.
> Bari Ari                 email: bari at onelabs.com
> O.N.E. Technologies
> 1505 Old Deerfield Road        tel: 773-252-9607
> Highland Park, IL 60035        fax: 773-252-9604
> http://www.onelabs.com

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