T
Tony Hill
Hi all
I was over at the Ace's Hardware message board, and I saw someone
complaining (again) about how the Prescott P4 chips were using more
power than the Northwood and how they felt that Intel's 90nm shrink
wasn't improving anything.
This got me thinking, just how much did the process actually improve
on a per-transistor basis, so I ran a few numbers and here's what I
got:
Willamette (180nm) 2.0GHz : 42M transistors, 71.8W TDP
Northwood (130nm) 2.0A GHz: 55M transistors, 52.4W TDP
Therefore we get 1.71W/MTrans for Willy and 0.95W/MTrans for
Northwood, or a reduction of 44%
Northwood (130nm) 3.2C GHz: 55M transistors, 82W TDP
Prescott (90nm) 3.2E GHz : 125M transistors, 103W TDP
Here we get 1.49W/MTrans for Northwood vs. 0.82W/MTrans for Prescott,
or a reduction of 45%.
If we were to ignore the cache then things would probably look even
better for the Prescott/Intel's 90nm shrink. Basically every
transistor added in the Willamette -> Northwood shrink were cache
transistors (actually, they only added 13M transistors while an extra
256KB of ECC cache should take up 14M transistors). However with the
Northwood -> Prescott shrink Intel increased the number of non-cache
transistors significantly (from about 25M to 65M transistors as a
rough estimate).
This actually suggests that Intel's 90nm manufacturing process is
doing quite well from a power consumption perspective.
Of course, the flip side to this discussion is that Intel doesn't seem
to have managed to get much performance out of those extra
transistors. Right now they seem to have a chip that is slower, clock
for clock, on most applications when compared to the Northwood. The
theory behind the Prescott is that it will allow for higher total
clock speeds than the Northwood and therefore higher overall
performance. However on the performance/watt scale (one that I've
mentioned as being increasingly important), it seems unlikely that
Prescott will ever match the current Northwood, let alone a 90nm
shrink of a Northwood. Even if Prescott manages to clock to 5.0GHz
while a 90nm shrink of the Northwood would only manage to clock to
4.0GHz it seems likely that, watt for watt, that 90nm "Northwood"
would be the better chip.
Still, when you get right down to it, it's definitely NOT all doom and
gloom for 90nm shrinks either for Intel or anyone else.
I was over at the Ace's Hardware message board, and I saw someone
complaining (again) about how the Prescott P4 chips were using more
power than the Northwood and how they felt that Intel's 90nm shrink
wasn't improving anything.
This got me thinking, just how much did the process actually improve
on a per-transistor basis, so I ran a few numbers and here's what I
got:
Willamette (180nm) 2.0GHz : 42M transistors, 71.8W TDP
Northwood (130nm) 2.0A GHz: 55M transistors, 52.4W TDP
Therefore we get 1.71W/MTrans for Willy and 0.95W/MTrans for
Northwood, or a reduction of 44%
Northwood (130nm) 3.2C GHz: 55M transistors, 82W TDP
Prescott (90nm) 3.2E GHz : 125M transistors, 103W TDP
Here we get 1.49W/MTrans for Northwood vs. 0.82W/MTrans for Prescott,
or a reduction of 45%.
If we were to ignore the cache then things would probably look even
better for the Prescott/Intel's 90nm shrink. Basically every
transistor added in the Willamette -> Northwood shrink were cache
transistors (actually, they only added 13M transistors while an extra
256KB of ECC cache should take up 14M transistors). However with the
Northwood -> Prescott shrink Intel increased the number of non-cache
transistors significantly (from about 25M to 65M transistors as a
rough estimate).
This actually suggests that Intel's 90nm manufacturing process is
doing quite well from a power consumption perspective.
Of course, the flip side to this discussion is that Intel doesn't seem
to have managed to get much performance out of those extra
transistors. Right now they seem to have a chip that is slower, clock
for clock, on most applications when compared to the Northwood. The
theory behind the Prescott is that it will allow for higher total
clock speeds than the Northwood and therefore higher overall
performance. However on the performance/watt scale (one that I've
mentioned as being increasingly important), it seems unlikely that
Prescott will ever match the current Northwood, let alone a 90nm
shrink of a Northwood. Even if Prescott manages to clock to 5.0GHz
while a 90nm shrink of the Northwood would only manage to clock to
4.0GHz it seems likely that, watt for watt, that 90nm "Northwood"
would be the better chip.
Still, when you get right down to it, it's definitely NOT all doom and
gloom for 90nm shrinks either for Intel or anyone else.
