Do consoles have integrated memory controllers?

[Fox5]

Just wondering since in this picture

There doesn't seem to be anything that resembles a northbridge. I would think everything either has a direct connection to the memory, or a direct connection to the cpu.

If consoles have integrated northbridges(or can skip them entirely), wouldn't this give their cpus a huge advantage over pc cpus, since it worked wonders for the athlons? Did the G3 and G4 cpus in apple computers have northbridges?

 

[Fafalada]

PS2 has memory controller integrated on EE.
GC has it on Flipper IIRC.
No idea about XBox.

 

[ERP]

The Northbridge is Part of NV2a and the MCPx is the southbridge.

 

[Fox5]

So does this give the consoles better performance than PCs?

BTW, I thought gamecube's cpu did have a direct link to the system memory....but maybe it does go through flipper. Actually it probably has to, I didn't pay attention to the names on the chips, but the gekko would have to go through flipper to reach the memory, and flipper basically is situated so everything can link to it.

 

[Guden Oden]

The analogy is somewhat flawed, as the term "northbridge" is an entirely PC-centric one built around the peculiarities of that platform.

The northbridge in the PC has traditionally consisted of stuff like memory controller, PCI bridge, AGP bridge, interrupt controller and other odds and ends needed for the mish-mash of tech that is an IBM compatible PC.

Consoles do not need all that crap, a northbridge would be a waste on them. They don't have PCI, they don't have AGP, they don't have the multitude of auxiliary buses and bits and bobs and odds and ends that PCs do.

It's not really possible to say a console is faster than a PC, because what kind of PC? Faster at what? It's too general a question to be possible to answer.

Pure guesswork would be that while the memory controller sits on the graphic chip, memory latency is lowest on the gamecube since it uses 1T SRAM (very low-latency RAM), but GC bandwidth is very low by today's standards - only 2.6GB/s IIRC.

PS2 has its memory controller integrated on the CPU die and consists of dual 1.6GB/s RDRAM channels, but it's not directly hooked up to the CPU, but rather sits on the internal CPU bus which has a lower total bandwidth than what the RDRAM channels can provide (about 2.4GB/s). RDRAM is often accused of being high-latency, but that is not neccessarily true. Also, RDRAM in PS2 is much different than RDRAM in PCs, where there might be as many as 32 memory devices hooked up in serial fashion one after the other on the same channel which means timings have to be relaxed and access time for the closest device is delayed on purpose to match access time for the farthest as not to cause havok on the bus. PS2 has just one device per channel and avoids those difficulties.

XBox is like a somewhat improved geforce 3 where there is a pentium3 CPU bus tacked on to the GPU - there is no traditional northbridge. The CPU uses the same memory controller as the GPU does, and there is no AGP bus either.

 

[Lazy8s]

The CLX in the Dreamcast is the memory controller and the PVR2DC renderer.

 

[Teasy]

Pure guesswork would be that while the memory controller sits on the graphic chip, memory latency is lowest on the gamecube since it uses 1T SRAM (very low-latency RAM), but GC bandwidth is very low by today's standards - only 2.6GB/s IIRC.

As system ram its quite comparable to new PC's. Since 2.6GB/s is the same bandwidth provided by PC2700 (166Mhz DDR) ram But of course that's only if you can fit all textures in 1MB of embedded video ram

BTW regarding when Fox5 asked if an integrated mem controller gives consoles better performance then a PC. I think he just meant does it give the console an advantage in that area compared to the way its traditionally been done on PC's.