all the 5 and 6 series lumias are classed as budget. the 530 has a quad core chip against the 520's dual core, but cos the 530's core is only based on a snapdragon 200 its actually no faster than the dual core chip in the 520 which is based on snapdragon 400, infact the 530 maybe even slightly slower especially on graphics, because the 530 has adreno 302 against adreno 305 in the 520. also the 530 doesnt have an ips screen like the 520.

the 525 has a dual core chip with same graphics as the 520 and an ips screen. but it has one thing over both the 520 and 530, it has 1gb of ram compared to the other two which have 512mb. older lumias can sometimes be better but you should make sure you go for a model that can be updated to windows phone 8.1.

some apps wont run on 512mb of ram although they are in the minority. some games may also refuse to run on 512mb, but to be honest you wouldnt be choosing a 500 or 600 series phone in the first place if gaming was important to you.

guys .i using 630. its nice