It just so happens that I have both the Lenovo Y510p SLI with I5-4200M CPU and the Acer V7-482PG-6662 for review at the same time (Y510p review) so I figured out I’ll do a little test comparing the GT 750M DDR3 in the Acer V7-482PG and the GT 750M GDDR5 in the Y510p.
Lets start with some specifications (I like colors and I’ll get better over time):
|Model||core (stock)||memory (stock)|
|GT 750M DDR3||GK107, core@967MHZ – 1167MHZ (Turbo boost)||DDR3@900MHZ (1800MHZ effective)|
|GT 750M GDDR5||GK107, core@967MHZ – 1058MHZ (Turbo boost)||GDDR5@1250MHZ (5000MHZ effective)|
The obvious thing is that the DDR3 version memory bandwidth is heavily limited compared to the GDDR5 version. I set out to test how much it influences the performance.
The Y510p SLI was disabled through the Nvidia control center and PhysX set to use the the same GPU. Also, the CPU were both fixed on 2300MHZ per core, making them quite similar in terms of performance since they are both 2-cores / 4 threads CPUs, with 3MB cache.
I tested these settings below with four configurations:
- GT 750M GDDR5 default clocks
- GT 750M GDDR5 with GDDR5@1500MHZ (3000MHZ effective)
- GT 750M DDR3 default clocks
- GT 750M DDR3 with DDR3@1080MHZ (20% increase)
|Model||GT 750M DDR3 (FPS)||GT 750M GDDR5 (FPS)||GT 750M GDDR5, MEM@1500MHZ (FPS)||GT 750M DDR3, MEM@1080MHZ (FPS)|
|Skyrim, highest settings@1080p||15||27||22||17|
|Borderlands 2, highest@1080p||23-25||40||32||25-26|
|Tomb Raider 2013, ‘ultra’ settings@1080p||17||25||22||20.5|
These finding are also supported by notebookcheck GT 750M tests – some of the games were tested with laptops that have both the GDDR5 and DDR3 version, like Metro: Last Light which show clear difference between the two with the GDDR5 version having around 13-14FPS on ‘ultra’ settings and the DDR3 version having around 9-10FPS : ~40% advantage. Moreover, these results are true for laptops with a high end power hungry I7-4700MQ CPUs (K56-3F).
We can also see in the notebookcheck results, that the picture changes when you play on low settings, in which case the load shifts to the CPU rather than the GPU which is underutilized – it happends in Dota2, Metro LL and GRID 2 on lowest settings, for example, while on high or highest settings, the laptops with the GT 750M GDDR5 GPU have the upper hand.
The conclusion is that the memory bandwidth has a significant role, even with a rather midrange GPU like the GT 750M. Furthermore, the difference can be quite high – 33% in Tomb Raider, up to 80% in Skyrim (!) and 60% in Borderlands 2 (!). These results are supported by notebookcheck GT 750M tests and also their tests of GT 650M GDDR5 in borderlands 2 vs GT 750M DDR3.
The practical conclusion is that you should notice if you get the DDR3 version or not. For example, the popular Asus brand sell their N550 series with a GT 750M DDR3 GPU for around $1000 while you can get the Lenovo Y510p with GT 750M SLI or the Sager NP7355 with GTX 765M, both way faster for gaming and both selling for around $1000 too (see all $1000 recommended gaming laptops)