4 Hardware bandwidth questions. (Related to ram,pci-e,cpu,gpu,sli).

Hello fellow netcitizens I have some hardware bandwidth questions for you:

Q1: Some websites specifications say:

1. The Athlon X2 4800 processor is limited to 6.4 Gigabyte/sec of memory bandwidth.
2. Intel Pentium Extreme Edition processor is limited to 6.4 Gigabyte/sec of memory bandwidth.

Case 1. Does this mean 3.2 Gigabyte/sec in both directions ?

Case 2. Or is it possible to have 6.4 Gigabyte/sec going in one direction ?

Q2: Some website specifications say (more or less):

PCI-E 16x slot is 8 Gigabyte/sec, 4 Gigabyte/sec IN and 4 Gigabyte/Sec out PCI-E 8x slot is 4 Gigabyte/sec, 2 Gigabyte/sec IN and 2 Gigabyte/Sec out PCI-E 4x slot is 2 Gigabyte/sec, 1 Gigabyte/sec IN and 1 Gigabyte/Sec out PCI-E 2x slot is 1 Gigabyte/sec, 512 Megabyte/sec IN and 512 Megabyte/Sec out PCI-E 1x slot is 512 Megabyte/sec, 256 Megabyte/sec IN and 256 Megabyte/Sec out

Case 3. So does this mean that PCI-E 16x slot is limited to 4 Gigabyte/sec in one direction ?

Case 4. Or is it possible to go 8 Gigabyte/sec in one direction ?

I'll assume Case 2 and Case 3 to be true.

Furthermore it seems current SLI motherboards when in SLI mode, turn the two PCI-E 16x slots into PCI-E 8x slots.

So the bandwidth that is available in SLI mode is the same as in SINGLE mode.

Anyway in both cases this would mean a maximum input for the graphics cards of:

Single: 4 Gigabyte/sec Input.

SLI: 2 Gigabyte/sec + 2 Gigabyte/sec = 4 Gigabyte/sec Input.

So that would leave 2.4 Gigabyte/sec for output. (from graphics card back to RAM)

Single: 2.4 Gigabyte/sec Output

SLI: 1.2 Gigabyte/sec + 1.2 Gigabyte/sec = 2.4 Gigabyte/sec Output.

So if I were to buy such an SLI motherboard it would be pointless to buy a graphics card which can handle more than 2 gigabyte/sec of input and more than 1.2 gigabyte/sec of output.

Q3: How much bandwidth can the new Nvidia GTX 7800 process for input and generate for output ?

Q4: How much bandwidth can the processors handle ?

Alternatively I could wait for new motherboards to come out with FULL BANDWIDTH PCI-E 16x slots.

Then the picture would look like this:

Single: 4 Gigabyte/sec Input.

SLI: 4 Gigabyte/sec + 4 Gigabyte/sec = 8 Gigabyte/sec Input.

BUT this is now limited by the the processor/memory controller: 6.4 Gigabyte/sec

SLI: 3.2 Gigabyte/sec + 3.2 Gigabyte/sec = 6.4 Gigabyte/sec Input.

That would leave no room for output... that s bad.

So better could be:

SLI: 2 Gigabyte/sec + 2 Gigabyte/sec = 4 Gigabyte/sec Input.

SLI: 1.2 Gigabyte/sec + 1.2 Gigabyte/sec = 2.4 Gigabyte/sec Output/

So I think I must come to the conclusion that with this processor/memory controller/bandwidth limitation waiting/buying this new motherboard will solve absolutely nothing. Since the bottleneck is in the processor/memory controller. (I think sometimes this is called the northbridge chip ? )

Anyway these dual core processors are very expensive.. so just upgrading them in the future for a little bit more bandwidth seems crazy.

My conclusion is as follows:

1. If the single card (the gtx 7800) is able to handle 6.4 Gigabyte/sec of input + output then I don't need SLI ;)

1. Otherwise I could buy into SLI as soon as the price has dropped to a certain point for the secondary graphics card.

The performance increase for SLI is: ( ( Final Performance - Original Performance ) / Original Performance ) *

100% ( ( 6.4 - 4.0 ) / 4.0 ) * 100% = 60%

Let's see the current price is $500 dollars.

So the price of the future card should only be 60% of the price which it is now.

$5 * 60% = $300 dollars

Alternative way of calculating:

The current performance is 100% procent.

The future performance will be 160% procent.

So the future total price should not exceed 160 * $5 dollars = $800 total dollars

We might already have payed $500 dollars so an investment of $300 dollars is warrented to get the same percentagual increase in performance hehehehehehhihihihi.

Ofcourse by then much better cards might have come out with even superior performance... though our current motherboards won't be able to benefit from them, simply because the bottleneck of 4 Gigabyte/sec in and 4 Gigabyte/sec out... but that would exceed the main memory/ram of

6.4 Gigabyte... so finally we more or less limited to 3.2 Gigabyte/sec for current motherboards/processors/chipsets ;)

Bye, Skybuck.

But at least he left out posting to alt.religion.wicca, which is a blessing

martin

'Skybuck Flying' wrote, in part: |I have already googled extensively for the words bandwidth, cpu, gpu, ram, | diagrams, netburst, hyper transport, maximum, graphics etc. | | Not once have I encountered a website which states the ammount of bandwidth | that a cpu, gpu, ram chip or transport technology can practically process or | generate. _____

Google + websites do not necessarily = learning. Websites are not the only place one can read. While googling and surfing you might also read up on how to post to a newsgroup why it is a good idea to read at least some of the posts in newsgroups before posting why it is a good idea to trim quotes when posting why it is a good idea to limit crossposting.

And you might also consider not asking a question if you don't want an answer. A different attitude might invite more answers to your questions.

Phil Weldon

| >

| |

I have already googled extensively for the words bandwidth, cpu, gpu, ram, diagrams, netburst, hyper transport, maximum, graphics etc.

Not once have I encountered a website which states the ammount of bandwidth that a cpu, gpu, ram chip or transport technology can practically process or generate.

The only things I have encountered are:

1. Occording to you apperently theoretical maximum bandwidths.

1. PC/System benchmarks, which ofcourse depend on many factors and combinations and are therefore bogus.

You claim to have knowledge of practical limitations of these devices.

I claim that you are full of bullshit since this information is not available on the internet, so there is after all nothing to read.

Ofcourse you are free to prove me wrong =D

Bye, Skybuck.

you:

can

data.

are

you:

Gigabyte/sec

direction

out

out

out

Megabyte/Sec

Gigabyte/sec

a

more

processor/memory

of

*

total

dollars

superior

of

for

nope, I said you didn't post to alt.religion.wicca

Have you tried a wood based storage device? There are many avaiable, in several dialects

can't be bothered, but you do seem to spend a lot of time sending stuff to newsgroups that would have absolutely no interest in your query

Think you should get back on the meds. You apparently are quite intelligent at first sight, try not to disprove it.

Happy Halloween

martin

Here is a nice start:

Technical specifications of GeForce 7800:

Graphics Bus Technology: PCI Express Memory Interface: 256-bit Memory Bandwidth (GB/sec.): 38.4 Fill Rate (billion pixels/sec.): 10.32 Vertices/sec. (million): 860 Pixels per clock (peak): 24 RAMDACs (MHz): 400

In particular notice this line:

Memory Bandwidth (GB/sec.): 38.4

Is this a theoretical or practically limitation ?

I would guess a practical since the rest looks pretty practical too.

However this information could be misleading.

What is ment with memory bandwidth in this case ?

Case 1: Main/PC/System RAM System Bus Graphics Card

or

Case 2: Onboard graphics card memory/ram communication.

My guess would be 2 !!!!! ( Because PCI express can't even handle that much bandwidth at the present time)

Which is still pretty f****ng amazing ;)

Here we are with an Athlon X2 4800 dual core which is able to "only" manage to pump around 6.4 GB/sec...

Gjee... ;)

Maybe I am wrong and maybe it's case 2 =D 'Skybuck Flying crossposted some questions to way to many newsgroups:

you:

can

data.

are

you:

Gigabyte/sec

direction

out

out

out

Megabyte/Sec

Gigabyte/sec

a

more

processor/memory

of

*

total

dollars

superior

of

for

You might be interested in getting a clue to what you're talking about ;)

Bye, Bye, Mister Trolly ;) :)

ram,

process

ram,

process

I wasn't talking to you so f*ck off mister troll numbero TWO hahahahaha.

Bye, Skybuck, The one and the only ! ;)

Hahahahahahaha. :P:P:P:P

--
Why are you here?

You would do well to go away, reconsider your attitude, taking on the fair advice that Phil has given you, and then try again, preferably after apologising for coming across as an ignorant arsehole. Does the saying "Do not bite the hand that feeds" mean anything to you?

--


Richard Hopkins
Cardiff, Wales, United Kingdom
(replace nospam with pipex in reply address)

The UK\'s leading technology reseller www.dabs.com

I was gonna say: "Go suck his dick"

But it's clear you already doing that lol.

Bye, Skybuck.

I agree Phil but it's obvious that this cretin is a troll so why feed him?