Moved: Diagonally Mounted Processors
The eMac, and the new PowerMac have processors that are diagonally mounted. Please don't link to the pictures of the prototype G4 though. If someone can dig up the pic of the eMac mobo and post it then please do so.
I was just wondering...what are the pros/cons of doing this what does it mean for next gen iMacs/Portables?
Perhaps utilizing this method daughtercards/mobos can be smaller? Maybe this tech will aid in the development of smaller notebooks, tablets, PDA/Phone hybrids, etc.
[ 07-28-2002: Message edited by: Jonathan ]</p>
I was just wondering...what are the pros/cons of doing this what does it mean for next gen iMacs/Portables?
Perhaps utilizing this method daughtercards/mobos can be smaller? Maybe this tech will aid in the development of smaller notebooks, tablets, PDA/Phone hybrids, etc.
[ 07-28-2002: Message edited by: Jonathan ]</p>
Comments
Yes, indeed, let's get an image here.
I can't imagine how they can fit stuff in a square container with stuff going slantwise
<strong>
I was just wondering...what are the pros/cons of doing this what does it mean for next gen iMacs/Portables?
</strong><hr></blockquote>
Any PCB designers here?
The 7200 had a diagonally mounted 601 btw.
Barto
A bit of simple examination reveals the following:
Consider a chip with an array of 5x5 pins under it ( not many i know ).
All the pins are to be routed to a slot.
Aligned to the slot, the mean number of pins that a single trace must pass by is 46/25.
It is hard to get lots of traces past the pins, and so either the board must have more layers, or traces must route around the chip.
When aligned at 45 degrees, the mean number of pins a trace must pass is 30/25.
Therefore there is less need for additional steps to be taken to route the traces.
[ 07-26-2002: Message edited by: Powerdoc ]</p>
However, if you look at the components around the cpu, you will see that they match those around the chip on the board, then you will be able to see the board itself.
<strong>The daughter card was not _clearly_ visible, and at first I thought the diagonal chip was the controller.
However, if you look at the components around the cpu, you will see that they match those around the chip on the board, then you will be able to see the board itself.</strong><hr></blockquote>
i agree here. the daughtercard is there - seems to be a little bit bigger than the older single-proc-G4-card... what makes me wonder is that there's no pic of the heatsink?
[ 07-26-2002: Message edited by: Krassy ]</p>
[ 07-26-2002: Message edited by: Powerdoc ]</p>
I don't work in our surface mount area, so I don't know what issues arise from placing at an angle either. Maybe I'll have to call them up and see if there are any issues to placing parts at an angle offset from the boards sides.
<strong>Usually there's a trace length reduction when chips are mounted diagonally, which can lead to greater performance, less power usage, etc. There's actually a <a href="http://www.xinitiative.org/"; target="_blank">web page</a> promoting the use of this layout technique.</strong><hr></blockquote>
If I'm not mistaken you are talking about physical chip design (inside the IC), whereas this thread was discussing mounting a chip on a Printed Circuit Board at a 45 degree angle.
Someone correct me if I'm wrong.
<strong>
If I'm not mistaken you are talking about physical chip design (inside the IC), whereas this thread was discussing mounting a chip on a Printed Circuit Board at a 45 degree angle.
Someone correct me if I'm wrong.</strong><hr></blockquote>
You are correct about the x initiative. It's aim is to allow for 45 degree routing of interconnects inside of chips.
However, woozle is correct about the the diagonal mounting having the benefit of shorter traces. If you notice Nvidia and SiS have both used diagonal mounting on their recent chipsets. It is especially helpful with timing requirements for high speed memory.
My knowledgable postition is based totaly on here say, but giving the concept a couple of minutes thought gave me the results about mean pins passed by a single trace.
Certainly real boards are more complex, but the basic idea still holds.
By making it easier to route traces, it is easier to keep them within their timing ( length ) and impedance requirements.
By reducing the complexity of the routing it may be possible to prevent a board from using additional layers to meet those requirements, reducing costs.
<strong>Diagonal mounting is more aerodynamic, so your computer can go faster!</strong><hr></blockquote>
if you assume they're tilted forwards... but with a 45 degree tilt, the glass-half-empty folks will insist it's tilted backwards
now if the daughtercard had a leading edge curve...
and the venturi holes were actually engine intakes...
and the secret partner wasn't nVidia but Rocketdyne...
this might be the promised iFlying car prototype :eek: