PCFormat Forum Archive

If two graphics cards are the same in almost every respect, but one has double the bit-rate of the other, how much of an impact does that have on the performance? Or, maybe a better question would be, what kind of impact does it have?

I just bought an MSi GT620, but the performance was only marginally better than my old setup, so I'm considering taking it back and getting a GT630 instead, with a slightly better clock speed, too. I just want to know whether it'd give me a noticeable improvement, though, before I fork out the balance (about 30% more).

Also, I hear that video RAM on one's card counts toward the operating system's RAM-seeing limit, so on XP 32-bit, a 2GB video card would leave me with effectively only 2GB RAM for the system. Is that true?

What "bit-rate" are you referring to?

No, it does not. Video ram and system ram are treated separately.

minvertedm wrote:If two graphics cards are the same in almost every respect, but one has double the bit-rate of the other, how much of an impact does that have on the performance? Or, maybe a better question would be, what kind of impact does it have?

I just bought an MSi GT620, but the performance was only marginally better than my old setup, so I'm considering taking it back and getting a GT630 instead, with a slightly better clock speed, too. I just want to know whether it'd give me a noticeable improvement, though, before I fork out the balance (about 30% more).

Also, I hear that video RAM on one's card counts toward the operating system's RAM-seeing limit, so on XP 32-bit, a 2GB video card would leave me with effectively only 2GB RAM for the system. Is that true?

what do you mean by "bit rate"

Hman wrote:No, it does not. Video ram and system ram are treated separately.

What he said

//I hope you are not still using windows XP, and why not buy a real card the 620 and 630 are if I am honest rubbish

I'm guessing he means 256bit vs a 512bit card, and yes, it makes a fair difference. Or at least, it used to. But there are a lot of other factors to consider as well, number of cores etc.

If you are referring to 64bit, 256bit, 512bit or whatever number used on the packaging it refers to the bit "width of the memory controller of the video card.

A wider bit width for the memory controller means it can transfer more bits in a single clock cycle. For example if we had two memory controllers, one is 64bit running at 1Mhz and one 124bit at 1Mhz. The second one would be twice as fast transferring 128bits in one second as opposed to 64bits for the former.

But then if the 64bit controller was running at 2Mhz and the 128bit one still at 1Mhz, the two would be equally fast since both would transfer 128bits in a second.

This means that you have to multiply the bit width by the memory frequency to see which is faster.

But as Syko stated things aren't that simple, a card with a slow gpu can have the fastest memory ever invented. But it will be slower than a card with a fast gpu even if it has slow memory.


Rather tell us how much you are willing to spend and we would gladly tell you what the fastest card for your money would be.