6/8 PCB Layers difference.

[eddy05]

I've gotten my ABiT Siluro GeForce 4 Ti4200 recently (Thanks mom!!!) and I was wondering about the difference between the PCB board.

In accordance to what I think I knew, GF4Ti4200 uses a 6-layer PCB board instead of GF4Ti4400/GF4Ti4600's 8-layer PCB board.

What's the function of the PCB board? What difference is there in a 6-layer and a 8-layer board?

Regards
- eddy05, the always-wanting-to-know-everything.

 

[PreservedSwine]

More stuff = More layers <------Layman


If you have alot of trace routes from the GPU, or you don't have alot of trace routes but alot of extra ground and power planes that you need to keep within Signal Integrity requirement to keep those fast memory busses nice and clean, you need more layers. Otherwise, try and squeeze too much into any one layer, things begin to overheat, resistance changes, and things no work right.

I hope this helps- adding layers to PCB's is expensive, thus the Ti4400 is really a steal right now, IMO

But I wouldn't be turning down any Ti4200's either- GREAT CARD!

 

[Rick]

While lossy signaling is probably one of the side effects fewer PCB layers, the plusses are excellent. Signal degradation can (and usually is) accompanied by a cleaner, smaller design and layout. So I consider this drawback negligable in many cases. From what I've seen, sometimes these enhancements lead to better performance, as seen witht he SiS 735 chipset for example. Simpler layout = better performance. Of course, whether this logic applies to your card is dependant upon how they squashed 2 extra layers of PCB into 6.

Best of all, fewer PCB layers means a far better price. Just a couple of layers make a big difference in this respect because the complexity and materials required for the product are greatly reduced.

I would consider 6 better than 8 for all intents an purposes.

 

[Per Hansson]

I'll have to disagree with Rick

If we take RAM as an example the high-quality RAM always uses 6-layer PCB's, this reduces interference a great bit, so a 4-layer one will be more "noisy"..

For GFX cards, more layers can oftenly mean much higher attainable speeds due to the reduction in noise, take a look at the new ATI 9700: it has 10 layers! (and I'm sure Nvidias NV30 wont have less!)

And lastly, take a look at AMD's just released 2400 and 2600+ CPU's, before they had 8 layers (Thourobread-A, that chip was barley able to hit anything higher than 2100mhz, but now when AMD added a second layer the chip is able to be overclocked to 3000+ speeds!!! (Thourobread-B)

The only downside to more layers is increased price...

 

[Rick]

I stand corrected then, Per.

 

[eddy05]

bwhahahaha...

Well as long as it worked fine, I'm alright with my GF4 Ti4200. BTW I noticed that whenever I played Warcraft III my system will jerk and lag during scenes with a lot of characters. Could that be due to the fact that I'm using only 64mb of Gfx RAM? I'm running on a 1.8ghz (Wi) CPU and I'm quite certain that it's not the fault of my CPU