iPad gfx mem

Quick one: How much gfx mem has the iPad and is it shared or dedicate?

 

The iPad is exactly like an iPhone 3GS in concern to it's GPU and Memory.

 

Errrr?

That would make it a quarter of the speed because the screen is four times larger...

 

Yes, dear. If you hadn't been away for so long, you'd have seen several threads about this. :roll:

But that's a bit of an oversimplification. The actual number is 5.12. And it's not necessarily slower. If you hit the cap, it doesn't get slow, like on a desktop; it just crashes. And the faster CPU allows for more draw calls, but you can't expect the polygons to be too big on screen, because then you get burned by fill rate.

The new iPhone is rumored to have 512 MB of RAM, twice that of the iPad or last year's updates. Its screen is 640x960, which means it will be a little faster than the iPad (provided the chip inside is the same A4). However, on the whole, due to lack of GPU upgrade, everything coming out this year is underpowered compared to last year, at least if you want a displayed resolution that takes advantage of the screen.

 

There is one SGX model above the iPad / iPhone 3GS, quite a jump both on fillrate and polygons per second. I want to say it is the SGX 545, but I can't remember. We all thought it was going in the iPad, but alas that didn't happen. Hope it shows up in tomorrow's iPhone.

 

It is SGX 545 right, thats above it I mean.


And no it won't crash if you hit the fillrate border. it will just drop in performance significantly as the fillrate bottleneck is an absolute one (its the max pixels the gpu can process).

using alpha (independent if blended or tested) is therefor a very risky thing on the ipad.


As for VRAM: As the 3GS, the iPad can use the full amount of available RAM. They don't have a hardset limit like the 1. and 2. gen devices with their 22.xmb (its 24mb - 2x Back Buffer)

 

I was talking about the entirety of RAM, as we don't get to use virtual memory on these devices because their flash disks aren't up to it.

 

for texture memory you never get to use paged memory not even on the desktop. if the RAM can't hold it, it will crash.
paging out the pci / agp textures is not allowed.


But yes on the iPad if you use more RAM than the device can offer you, you get killed. But on the ipad / 3GS there is no fixed amount of VRAM anymore so your program code, movies, sounds etc define how much memory there is left for the textures

 

If the new iPhone does indeed have 512 MB of RAM, then it's basically in the territory of a current generation console, memory-wise. I'm assuming that sharing this memory makes for a very slow GPU, though. Any idea how much slower that actually makes things?

 

all iphones always have had sharing memory actually.
even the first 2 generations (but at a fixed size)

and its not slow or bad as it is all integrated on the desktop. the stuff is designed to be performant, efficient and energy efficient.

nothing will change performance wise (aside of it getting faster anyway assuming it has the SGX 545, otherwise the iphone 4th gen is doomed as much as the ipad with its 960x640 screen resolution.)

 

Yeah, I've recently been hit by that fatality too.


More details about different CPUs + GPUs here :



Yeah, Samsung is claiming 90 millions T/s.

This device is making some real noise this month on the web anyway.

We can expect the iPhone 4G to have the same performances, I guess.

Considering the iPad has a 1.83 MT/S in full screen resolution, we can say that the forthcoming android phones like the Galaxy S will not repeat this iPad framerate dramatical loss.

edit : here's a benchmark from CNET Asia about the Galaxy S against Nexus1 and Desire. Smoking, considering those were made under 2.1, not 2.2.