Video RAM - how much do you really need?

Anach · Unread post by **Anach** » Thu Nov 08, 2007 3:18 am

http://www.yougamers.com/articles/13801 ... ally_need/

The first 3D accelerator add-in boards (merely called graphics cards today) appeared on the market over ten years ago and whilst the processing power and raw capabilities of the main chip have increased beyond all expectations, the amount of memory on the circuit board has increased rather more slowly. However, the latest games are becoming ever more demanding on the resources a PC has to offer. So if you're out to buy a new graphics card, what do you do - buy the one with the most memory, the fastest memory, the latest memory type? We delve into the mysteries of video RAM and take a brief look at the different types and what it gets used for, before we examine just how much your graphics card really needs.

Ah, the good old days of 4MB of EDO DRAM. Amazing that ten years of development have made it utterly useless - the main menu screen of Crysis needs 20x that amount of VRAM alone

Don't be naive in thinking that games won't be using more than 512MB any time soon, because they already are in certain cases. We're still some way off before developers start making games that require half a gigabyte of video RAM to play properly, but if you want the best possible visuals, get the most RAM that you can.

A'Ton Sands · Unread post by **A'Ton Sands** » Thu Nov 08, 2007 3:54 am

No surprise there, the more memory the more 'screens' can be buffered.
It is much faster to constuct a screen in memory and then blit it to the the actual video port than to try and construct it directly onto the port, the more memory the more screens can be made and the smother the video.

Iakimo · Unread post by **Iakimo** » Thu Nov 08, 2007 5:30 am

Something I don't understand yet is how vid-card memory affects operating-system memory caps. For example, I'd heard that the theoretical memory cap for Windows XP was 2 gigs, while Vista goes beyond that. Anyone feel like waxing educational and 'splaining how the memory on a card affects this total-system-memory limit? Like, if you have 2 Gb of system RAM, is there any practical benefit to having a video card with another half-a-gig of on-board RAM in an XP-based system?

And, does the XP Emulator built into Vista-64 also have the 2Gb limit?

A'Ton Sands · Unread post by **A'Ton Sands** » Thu Nov 08, 2007 6:09 am

Put simply, video memory should not impact on system memory.
There are two reasons why you dont want to use system memory as Vedeo memory.

1) Speed, graphics memory should be the fastest memory available and with the specialised busses reading and writing to graphics memory is very fast in comparison to system memory.

2) Using system memory would mean that the memory used for graphics would then be under control of the system memory management and subjected the the same paging and contention as processes compete for its use, not a good thing if you want fast smoth graphics.