3Dnow: AMD K6-2 technology
 
  1. K6-2 features
  2. K6-2+ features
  3. K7 features
  4. 3Dnow Architecture in K6-2
  5. 3Dnow instructions
  6. 3Dnow Aspects (good, bad...)
See also CPUspecs.html

K6-2 features: 
also known as K6-3D (initial name)
0.25 microns
from 300 MHz (300 and 350 available)
100 MHz bus speed
9.3 Million transistors
Superscalar MMX
(For more informations go to CPUspecs )

As you can see it has lots of new characteristics, and most of them are important because they show what future CPUs could be.

The project name of this processor was K6-3D but now it is sold as K6-2.
The E-Mail announcement was posted Thu, 28 May 1998.
This processor has a principal aspect which is the most important modification compared to K6-1: the 3D unit.
And this 3D unit is the first for PC market !
AMD has done a very good work and provides other good options on the new CPU.
A thinner transistor size offers the ability to create cooler chips, and now we can buy 300 and 350 MHz processors.
We can expect also 400 and 450 MHz version during 1998-1999.
The second appreciable aspects after 3D instructions is the new 100 MHz bus speed; this CPU uses a special socket7 named Super7 (yes, it's a PGA processors and I am happy to see that Socket processors are not already dead :-).
This socket is a piece of the motherboard enhancement: a faster bus speed between CPU, mobo and Memory !!!
And this is a 50% speed increase (from 66.6Mhz to 100 MHz) or 70% (from 66 MHz to 113 MHz).
Some Mobo can provide 113 MHz frequency !
Of course we can't expect these speed increases (50% 70%) because PCI buses (PCI-1 and AGPX1) still are at 33 MHz . But an X2 or X4 AGP speed (X2=67Mhz, X4=133Mhz) will take advantage of the new motherboards.
It seems that today the difference between 66 MHz and 100 Mhz memories isn't more than 20-30%.
Some people say the K6-2 is better than a PII: i think that it is wrong. BUT this is only for a large use of the processor, because for special 3D softwares (games) a K6-2 is really interesting, it is cheaper and can be faster !

K6 III features: 
also known as K6+-3D (initial name)
L1 and L2 cache onchip (L3 cache on Mobo :-)
350... ...400... ...450... ... Mhz
ship in 1999 (not sure!)
21.3 million transistors
(For more informations go to CPUspecs )

This processor isn't only a big version of K6-2 but it will also be a really powerful CPU with L1, L2 and L3 cache; L1 and L2 will be on the chip and both exactly at the processor frequency (like the best PII: Katmaï).
L2: 256 Kb, 4 way set associative.
It seems that it will also respect socket7 compatibility.

K7 features: 
BGA chip (as PII); Slot1 compatible (Beurk !!!)
(Form more informations go to CPUspecs )

3Dnow Architecture in K6-2:
This new unit supportsSIMD FPU and SIMD INT instructions.
SIMD: Single Instruction, Multiple Data; like MMX, it can manage several values in only one instruction.
The 3D unit registers are shared with the 8 MMX registers (8x64bits; MM0,... ...,MM7)
The switching between MMX/FPU/3D units is faster, it takes less clock cycles.
These 3 units can work closer, enabling more speed and less wait-states.
3D registers are compatible with IEEE-754 single precision format; it takes less time to compute instructions and gives results appropriate for 3D gaming, games does not need complex FP results.

3Dnow instructions:
There is 21 new 3D instructions, made for 3Dpersonnal softwares.
It means that these instructions has not been made for professional, scientific or economical use.
It is made for 3Dgames, and can be used in 3D renderers (but it is not the goal).
There are already games which have 3Dnow patches (Quake...).
These patches are often made for a 3Dnow-Direct3D combo (or 3Dnow-glide).
 

3Dnow Aspects:

Bad

Good