8 GBs of RAM or better GPU + SSD?

Mike, daca ai de ales intre unul cu 4GB de RAM si placa video mai buna si unul cu 8GB de RAM si un chip grafic mai modest, mergi pe cel cu grafica mai buna.

Tine cont de urmatorul lucru: memorie RAM poti adauga foarte usor si e foarte ieftina in comparatie cu alte componente. Un SSD deasemenea se poate adauga usor. In schimb, o placa video sau un procesor superior nu le poti instala in laptop - 1 pentru ca nu le gasesti, 2 pentru ca nu se pot schimba (GPU nu e pe socket - unele procesoare sunt, dar suportul pentru ele depinde de BIOSul placii de baza...deci intri intr-un put si ramai acolo d.p.d.v al CPU si GPU).

Eu as merge pe cel cu piesele care nu se pot schimba mai bune.

D.p.d.v al chipului grafica, 720M si 820M sunt cam la fel cu cateva exceptii in favoarea lui 820M.
Rata de transfer de pixeli este cu circa 25% mai buna pe 820M. Ai suport pt OpenGL 4.4 (vs 4.3 pe 720M), consumul este cu peste 50% mai mic pe 820M (15W vs 33W pe 720M) , deci bateria, in cazul in care e de aceeasi capacitate pe ambele laptopuri, ar trebui sa dureze ceva mai mult pe cel cu 820M. De altfel, atat GT720M cat 820M sunt bazate pe arhitectura Fermi - deci sunt comparabile atat diferentele de eficienta cat si ceasurile la care ruleaza, optimizarile fiind aceleasi pe ambele chipuri.


DAR, acuma-i acuma....daca chipul grafica este 840M - ala e considerabil mai performant ca 720M. GT840M este bazat pe arhitectura Maxwell - cea mai noua arhitectura de la nVidia - 720M este bazat pe Fermi. Latimea de banda pe Maxwell fiind cu vreo 20% mai mare, procesoarele shader fiind cu 400% mai multe (384 in comparatie cu 96 pe 720M). Scorul de performanta pe shadere este cu vreo 330% mai buna. Dispui de 50% mai multe unitati de procesare a texturilor, care la randul lor sunt transferate 147% mai rapid (24.7GT/s vs 10GT/s), iar rata de transfer de pixeli este si ea marita la 8.2 mii de pixeli (de la 5 mii de pixeli). Sunt diferente considerabile de performanta intre cele doua, iar consumul este identic (33W) pe ambele chipuri.


ENGLISH:
Mike, if you've gotta choose between one with 4GB of RAM and a better GPU and another with 8GB of RAM and a more modest GPU, go with the one with the better GPU.

Keep in mind the following: RAM can easily be added and it's very cheap compared to other components. An SSD is alos easy to add. On the other hand, a better GPU or CPU can't be installed in a laptop in the form of an upgrade - first because you can't find them like you'd find desktop parts, 2nd because they are not meant to be uppgraded (the GPU is not socketed - some CPU are, but support for them depends on the motherboard's BIOS...so you'll basically find yourself at a dead end on that matter).

I'd go with the one that has better non-upgradeable components.

From a GPU perspective, the 720M and 820M are similar with a few exceptions favoring the 820M.

Pixel transfer rate on the 820M is around 25% better. You'd also get support for OpenGL 4.4 (vs 4.2 on the 720M), while power consumption would be over 50% lower on the 820M (15W vs 33W on the 720M), so battery life should be better on the laptop with the 820M as long as the rest of the components on both laptops have similar power consumption.
Both the 720M and the 820M are based on theFermi architecture - therefore they are quite comparable in terms of power efficiency and clockspeeds, the architecture optimizations being the same on both chips.

BUT, here's the thing...if one of the laptops comes with the GeForce GT840M - that one is considerably more powerful than the 720M. gt840m is based on the Maxwell architecture - the newest one from nVidia - the 720M is based on Fermi. Memory bandwidth on the Maxwell chip is around 20% higher, the chips features around 400% more shaders (384 vs 96 on the 720M). Shader performance score is around 330% better on the 840M. You also have 50% more texture processing units, which in turn get textures through the pipeline 147% faster (24.7GT/s vs 10GT/s). Pixel transfer rate is also increased at 8.2 thousands of pixels (up from 5 thousand pixels per second). These are considerable differences between the two chips - all while the power consumption remains the same (33W).