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Some general GPU questions.

Omaeka

Omaeka

Omaeka

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Sorry for yet another topic but you guys are really knowledgeable. :o :p

1. What does V-RAM do? I know it's used for display resolution, but otherwise I'm clueless.

2. What does the Core Clock do? This I have absolutely no idea about, I was told recently but I kinda forgot. :D

3. What does the Memory Clock do?

4. Do the shaders do anything other than SSAO and shaders/lighting?

5. What is the Memory Interface?

6. What are processing cores?

7. Is there anything at all I've missed that graphics cards have that directly control performance?

Also, don't mean to be cheeky but would it be possible to know what each is responsible for? i.e: VRAM handles anti aliasing (probably wrong :p).

Cheers!
 
The easy answer is that they don't work in isolation like you're asking. They all work in harmony to deliver performance. Some effects will tax certain parts over others.
 
Are any of the settings more important than others? I'm really interested in knowing what V-RAM does though, I know that resolution is solely dependent on V-RAM?
 
Omaeka said:
Sorry for yet another topic but you guys are really knowledgeable. :o :p

1. What does V-RAM do? I know it's used for display resolution, but otherwise I'm clueless.

Picture a GPU like a mini computer. You have a CPU (the GPU), you have a MOBO (the PCB everything sits on) and you have sticks of memory (VRAM). With the GPU being very much like a mini computer, when windows loads, data must be stored into memory and the same with a GPU. VRAM is faster than our PC ram and game information is stored into this VRAM, so the GPU can quickly get to the information stored. At the top end of video cards, the VRAM is generally GDDR5.

2. What does the Core Clock do? This I have absolutely no idea about, I was told recently but I kinda forgot. :D

The Core Clock is your CPU's speed if you like. If you leave it 'as is', it will happily do the intended tasks at the set speed. If your CPU was set at 3.6Ghz, that would be your Core Clock and with the GPU speed, you May see it as 1067Mhz (1.067Ghz) that would be your Core Clock. If you increase the core clock, fps will improve as the processor is working quicker than intended. Decrease the clock and it will slow down fps.

3. What does the Memory Clock do?

Very much like any clock. Increase the memory clock, and it will improve reading/writing times of the data from question 1. The quicker the data is read/written, the quicker the fps (frames per second) can go.

4. Do the shaders do anything other than SSAO and shaders/lighting?

Yep, shaders are in control of effects as well as lighting.

5. What is the Memory Interface?

You may have seen me mention the 256 Bit bus of the 680 is the limiting factor against the bigger bus of the 7970 at 384Bit (in previous threads). Now look at this like it is a massive race track Nvidia has 256 lanes of race track and AMD has 384 lanes. Each lane has a car on and Nvidia's cars travel at 60.8 MPH and AMD's cars travel at 55 MPH, the race is a mile and at the end, who would have the most cars across the finish line? AMD of course and this is why AMD have a better memory interface than Nvidia. (Best way I can describe that sorry).

6. What are processing cores?

This is where we can't compare Nvidia clock speeds with AMD's (like a few have). Nvidia uses 'Cuda Cores' (1536 of them) and AMD use 'Stream Processors' (2048). You would think that having more cores/processors, that would be better but in this question, it doesn't work like that. A Cuda core is more efficent than a stream processor and the architecture from each company varies massively.

7. Is there anything at all I've missed that graphics cards have that directly control performance?

There are a ton more questions like Dye sizes but that starts going way over my head. I sucked at math at school (25 years ago) and I am no better now and math plays a big part of further questions.

Also, don't mean to be cheeky but would it be possible to know what each is responsible for? i.e: VRAM handles anti aliasing (probably wrong :p).

Cheers!
Click to expand...

Hope that helps you understand a little better. I tried to explain it as simple as possible but I am useless at explaining things.
 
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gregster said:
Hope that helps you understand a little better. I tried to explain it as simple as possible but I am useless at explaining things.
Click to expand...

Mate those are perfect and well explained! I did kinda have an inkling that it works the same as a mini computer but I thought I'd be wrong as I usually am. :p

How important is core clock? I noticed that's the difficult one to increase without the temperatures climbing too much. The core clock is effectively the same as the CPU meaning (i5-3570k 3.4Ghz) < it's that part? Or is the core clock the same as an entire CPU unit not just it's speed?
 
Yep, spot on. I5 3570K at 3.4Ghz/GTX 680 at 1.17Ghz. Take walking/jogging/running as an example. When you walk, you can maintain a decent temprature when getting from A to B but you will not get there very quickly. Start jogging from A to B and you will get there quicker but you will be warmer and if you run from A to B, you will get there even quicker but you will be getting hot.

Bad example I know but take a GPU at 1117Mhz (walking) start making that core clock do 1200Mhz (jogging) and it will be getting warmer and push it to 1300Mhz and it will be getting Hot. Unlike my walk/jog/run methodology, a GPU can perform these tasks easily with adequate cooling. I water cool my CPU and GPU's which allow for hotter core temps but because of the cooling properties of water over air, water is more effective at cooling than air, hence you can achieve higher clock speeds. Take 8 Pack as an example. If you look at the 3DMark11 thread, he has crazy scores compared to water or air cooling because he uses Liquid Nitrogen to keep the core cool.

It is still chip dependant because you will still need a goos piece of silicon to get these high clocks but you could have the same silicon on an air cooled GPU and not be able to see the same clock speeds as LN2 because temps will stop you from going any higher.
 
Well I get what you mean. So basically with the mini computer theory, the VRAM works like actual RAM does. With that being said, could you look at each piece of the game as programs on a computer? i.e those textures over there are an internet browser, the aliasing is i dunno, a anti virus program in the background and so on, and when all of those together start to require more memory than the GPU has, just like a computer would with its RAM, it'll start to get bad performance? This mini computer analogy is brilliant. :p
 
Omaeka said:
Well I get what you mean. So basically with the mini computer theory, the VRAM works like actual RAM does. With that being said, could you look at each piece of the game as programs on a computer? i.e those textures over there are an internet browser, the aliasing is i dunno, a anti virus program in the background and so on, and when all of those together start to require more memory than the GPU has, just like a computer would with its RAM, it'll start to get bad performance? This mini computer analogy is brilliant. :p
Click to expand...

A very good way to look at it and if you run out of VRAM, the GPU will start to use your computer RAM as back up (DDR3 is much slower than DDR5 and hence why fps drop to ~<15). If your computer runs out of ram, it will use a HDD/SSD to borrow memory from by reading/writing to that.
 
So normal memory RAM in your PC can actually be important for performance? :o I take it the speed and power of the RAM means more than the amount of it, do you know what the performance of the HyperX Genesis RAM is? Would getting stronger more efficient RAM be a worthwhile performance boost? Or will I simply never run out of 3GB VRAM?
 
The lower the resolution of a monitor, the less VRAM is used (1280*720) and the higher the resolution, the more VRAM is used (5760*1080 (my resolution)). I have 2*2GB 680's but that doesn't mean I have 4GB available to use, it will still only use the 2GB available.

With the 2GB available to me, I have only once been able to use more than what I have and that was by pushing 8*MSAA and everything else on ultra in Far Cry 3. Now you may think "Get the 3GB 7970's then and this will allow you to play at full ultra with 8*MSAA" but and this is a big BUT... Let's say I had the 4GB cards (2*4GB 680's (still only 4GB available to be used)), that would allow me to play with settings at ultra and 8*MSAA but because of the sheer amount of processing power needed, my fps would be around 15-20 at a guess (was just over 25 with 6*MSAA and full ultra) and the question then comes "Is that playable?" It would be a big "Nope" from me.

I don't know what you game at (resolution) but with 3GB, you will never run out of VRAM if you game at 1080P. Somebody might want to be argumentitive and say "Wrong" but I will stand by that fact and when the time comes that 3GB isn't enough, neither will the processing power be enough.

Time and time again I have seen arguments that say 2GB isn't enough at 1080P because in BF3 I have seen 2.4GB being used. What is happening is the VRAM is caching data/textures and storing them for later on. This doesn't happen if the game required 1.9GB of VRAM and you only had 2GB as opposed to 3GB but there wouldn't be a single fps difference with storing VRAM and not storing VRAM.

TL: DR, no need to get faster computer ram, as DDR3 1600 - DDR3 2133 will make very, very little difference in gaming.
 
I learnt all I know from the trusted Peter and Jane books :p

peter-and-jane1.jpg
 
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