Confusion. AMD, why?
First of all, a table
|GPU Model||Core||Core Speed||Memory type@speed – bandwidth||Max memory capacity|
|Radeon HD 7670M||Turks||600MHZ||DDR3@900MHZ – 28.8GB/s|
GDDR5@900MHZ – 57.6GB/s
|Radeon HD 7690M||Turks||600MHZ|
|1. GDDR5@900MHZ – 57.6GB/s|
2. DDR3@900MHZ – 28.8GB/s
|Radeon HD 7690M XT||Turks||725MHZ||GDDR5@900MHZ – 57,6GB/s||2048MB|
The Radeon HD 76XX is AMD highest offer for the midrange graphics. As a rule of thumb, you’ll get something like medium to high settings in latest games, depends in resolution, cpu and ofcourse, the specific GPU model. The top of these cards are the Radeon HD 7690M/XT GPUs cards, but all of them are based on the same chip – the Turks (WhistlerPro/XT/XTX) which variations in memory bandwidth and core clock speeds and are all a renamed and slightly changed HD 6650M / 6750M / 6770M radeons.
Let’s start by telling the difference between the Radeon 7670M and the 7690M cards: As you can see in the table, they are very similar. The 7670M GDDR5 version seems like the 7690M GDDR5 version only that the Radeon 7670M GDDR5 has a 1024MB memory limitation while the 7690M has 2048MB memory limitation. Meaning, in fact, that the Radeon 7670M offers, most of the time, the same perofrmance as the Radeon 7690M. AMD tries to confuse us. The GDDR5 cards have a greater memory bandwidth, but it’s most of the time not necessary as these cards can’t make use of it anyway (however, it might be useful). You’ll better check exactly what you’re buying before buying it.
Now, the 7690M has another two variants – the DDR3 version and the XT version. The DDR3 version offers 125MHZ higher core clock speed (and lower bandwidth then the GDDR5 version) while the 7690M XT offer this 125MHZ increase plus a GDDR5 memory and therefore it’s the fastest of them all.
So, which gpu should you choose?
The 7670M offers most of the [regular] 7690M performance (or even the same performance) for much lower prices – that’s great. If you know you’re going to run FullHD scenes and up then you might want to take the Radeon 7690M with 2GB memory card, but usually, you won’t notice significant performance gains.
However, the Radeon HD 7690M XT offers the most performance and judging by the raw numbers – about 20% higher performance than the slowest 7670M DDR3 model. The 7690M XT usually found in the more expensive laptops – 800$ and up and in that case you might want to check the competitors – the Nvidia GT 555M / Nvidia GT 640M-650M and Radeon 7700M series cards’ gaming laptops. They should all offer the same or higher performance then 7690M equipped laptops.