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Nvidia launches GeForce GTX 675MX and 670MX

QuizzicalQuizzical Posts: 17,390Member Epic

For months, Nvidia has had a gaping hole in their mobile lineup.  The GeForce GTX 660M was based on the generation's slowest GPU chip--from either vendor.  The GeForce GTX 680M was a very nice card, but cost a fortune.  Laptop vendors don't publish absolute prices, but only differences in prices between various cards, but if you got a GTX 680M, you were probably paying about $700 or $800 for the video card alone.  That's fine if you were planning on spending $2500 on a laptop, but not if you're looking for something a little more budget-friendly.

In between, there was the GeForce GTX 670M and the GTX 675M.  Unfortunately, those were old Fermi rebrands.  You could cope with the massive heat output in a desktop, but not a laptop.

So you buy AMD this generation, right?  The Radeon HD 7970M certainly looks good in terms of specs and price.  But in previous generations, going AMD had typically meant keeping the discrete card running all of the time, as AMD didn't bundle their own drivers with Intel video drivers for integrated graphics, the way that Nvidia did.  That's fine for some purposes, but it will kill your battery life.

But no, this generation, Clevo decided to use AMD Enduro switchable graphics, rather than leaving an AMD card running all the time.  That meant no driver updates.  It also ran into a rather problematic glitch where AMD switchable graphics wasn't able to use the full PCI Express bandwidth, which hurt performance badly.  A 7970M was still faster and far more efficient than previous generation cards, but not nearly as fast as it should have been.

For all the promise of 28 nm, the generation is nearly over and neither side had something suitable for $1500-$2000 gaming laptops on the market.

Today, Nvidia fixed that with the launch of the GeForce GTX 675MX and GTX 670MX.  The model number hole between the 660M and 680M was already filled by the 675M and 670M.  Rather than getting creative by having the third digit be something other than 0 or 5, or calling a card a GTX 665M (and thereby conjuring comparisons to the disastrous GeForce GTX 465, a marketing no-no), Nvidia marketing decided to add an X onto the end.  But contrary to the similar names, the GTX 675MX has nothing to do with the GTX 675M, and likewise if you subtract 5 from the model numbers.

The short story is that the GeForce GTX 675MX is a severely cut down GK104 die, with only 5 of the 8 SMXes active.  The GeForce GTX 670MX is a fully-functional GK106 die.  With the same clock speeds, they should have identical GPU performance.  The difference is in video memory, where the GTX 675MX has four memory channels at 900 MHz, while the GTX 670MX has three channels at 700 MHz.  Both are more expensive than the GeForce GTX 660M, of course, but not outlandishly so--and they're cheaper than a Radeon HD 7970M.

All is not lost on the AMD front, though.  AMD recently launched their first laptop drivers for discrete switchable graphics.  A hotfix for the PCI Express bus problem is currently being tested and due for public release next week.  Those who bought a 7970M early on won't be left out in the cold.  Hopefully this will mean that we see some laptops equipped with a Radeon HD 7870M shortly, too.

More generally, all up and down the lineup, Nvidia seems to have bet that more memory capacity and more GPU performance will win, while AMD has bet that more memory bandwidth will win.  A GeForce GTX 680M has considerably more GPU power than a Radeon HD 7970M, but only 3/4 of the memory bandwidth.  A GeForce GTX 670MX has a little shy of double the GPU performance of a Radeon HD 7870M, but only 5% more memory bandwidth.

So which side is right here?  On memory capacity, from a performance perspective, AMD is right and Nvidia is wrong.  It really is that simple.  But they probably both knew that a long time ago.  Nvidia is betting that customers are stupid and will think that more video memory means a faster card, and from a marketing perspective, they might be right about that.  Maybe.

Where it gets more interesting is the GPU performance versus memory bandwidth tradeoffs.  Here, it's the same story in desktops, where Nvidia went for more GPU performance while AMD went for more memory bandwidth.  And who bet correctly?

For older games that have MSAA (or maybe SSAA through drivers) as their only anti-aliasing options, AMD wins.  But as post-processing anti-aliasing effects such as FXAA replace the traditional MSAA, GPU performance matters a lot more and video memory bandwidth less.  In that case, Nvidia wins.

Assuming that the transition to post-processing anti-aliasing continues and MSAA dies out (which it should, but then, DirectX 9.0c should have died out by now, too), Nvidia has the more forward-looking architecture here, and there's a good chance that in games that launch two or three years from now, an Nvidia card would do better as compared to an AMD card in today's games.  Don't expect miracles; this isn't going to magically double the performance of Nvidia cards.  But movement of 5% in Nvidia's direction is a realistic possibility.

Furthermore, if you're comparing two cards that are both plenty fast enough in older games today, it doesn't matter which card is faster.  All that matters is how they'll perform in the future, more demanding games, where both cards might not have far more performance than you need anymore.

This only applies if we're comparing Kepler to Southern Islands.  In particular, it doesn't apply to Fermi, which still is and always will be a train wreck.  But AMD didn't regress here; Nvidia simply got better.  Fermi didn't scale well to highly demanding cases.  Kepler fixed that.


  • DurrayDurray NorwichPosts: 182Member Uncommon

    I love your work mate,

    Its great to see in depth pieces about hardware on this forum.


    As a side note I am looking currently at getting a new laptop and was thinking of one with a nVdia 650M inside. 


    For around £700 ($1000?), so that it could play most games decently. Do you think this is a wise decision? Is there an AMD alternative out there?


  • QuizzicalQuizzical Posts: 17,390Member Epic

    A GeForce GT 650M can come with either DDR3 or GDDR5 video memory.  The advantages of DDR3 is that it's lower power and much cheaper.  The advantage of GDDR5 is that it's much higher performance--typically 2-3 times the memory bandwidth, depending on clock speeds.  A GeForce GT 650M with DDR3 memory is somewhat crippled by memory bandwidth.

    Laptop cards are hard to get good benchmarks on, but the analogous desktop cards are the GeForce GT 640 (DDR3) and GeForce GTX 650 (GDDR5).  Both cards are way overpriced in desktops, so Nvidia didn't send either out for reviews, but you can see how they compare here:,3297.html

    As you can see, the GTX 650 crushes the GT 640 at basically everything.  And again, they're the same GPU chip, just paired with DDR3 or GDDR5 memory.  The GTX 650 is also clocked a little higher, but the clock speed difference is much smaller than the performance difference.  I'd actually expect the difference between the DDR3 and GDDR5 versions of the GeForce GT 650M to be a little smaller than the desktop cards, but it's likely to still be large.

    The GeForce GT 650M with DDR3 memory will be able to play just about any game, though often it will be at reduced settings.  If you could find a GDDR5 version of the card for the same price, that would be significantly better.

    As for an AMD alternative, laptop vendors mostly haven't bothered with AMD video cards this generation.  I'm only aware of three laptops off hand that even offer a current generation AMD video card, and two of those are the high end 7970M, which is way out of your budget.  The third is a DDR3 7730M that HP offers in at least one configurator--but they don't let you configure your laptop if you buy it in Britain.


    But let's back up a moment.  Why do you want a gaming laptop at all?  Your budget is easily enough to get a very nice gaming desktop.

  • DurrayDurray NorwichPosts: 182Member Uncommon
    I already have quite a nice rig.
    I7 2600, gtx 570, 8gb RAM.

    Sadly work is going to have me travelling a lot in the Next 1-2 years so I need a new laptop anyway, for work. I want to be able to enjoy some games in my down time still. It would be quite difficult to transport my desktop around.

    sent from my HTC so sorry for typos!
  • jdnewelljdnewell Spring Hill, TNPosts: 2,151Member Uncommon

    The job I took a few months ago has me traveling alot as well. So  i also wanted a laptop mainly for work but that would also play games at a decent performance.

    I personally was on a lower budget than you are, around $700 roughly. I bought one of the HP laptops with the 7730M in it. I also upgraded to a 7200rpm hard drive & got 8g ddr3 1600mhz RAM.

    I must say for the money I spent on it that little laptop does very well. I can play GW2 at medium, TSW at low/med, Borderlands 2 medium/high, Skyrim medium, D3 high, TL2 High, ect ect.

    Not the best  by any means, but easily playable for travel and not a huge investment. Granted I use my laptop more for work than gaming. Excel, Word, emailing, web browsing our sales site for products, ect.

    What i usually do is bring along an HDMI cable and use the in room LCD TV with an x box controlled to play games such as skyrim & Borderlands 2. I also use it to stream movies or watch DVDs on the television as well.

    If your looking for a laptop strictly for gaming you can probably do better. If your looking for something to do some light gaming on at night after work when you are on the road then this fits the bill perfectly. Mine cost me less than $700 before state tax ( which is a horrible 9.5% ). Your taxes and shipping may differ, total was $737 for mine.

    For what I use it for that laptop is perfect. Games, media, streaming, and all my work applications. Plus its 15.6in screen/size makes it fairly light and easily portable for travel.

    I made the mistake years ago of buying an expensive " gaming " laptop. Never again will I waste the money on something like that. I personally would rather have a decent laptop for a good price that can also play games at an acceptable level. Spending a ton of money for a " gaming" laptop that will be outdated within 12 months isnt a good value for the money you spend.

    Just my 2cp. Hope that helps. Figured I would chime in since I also travel and like to game some on the road. =)

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