how to speed up my ZTE Z793C I have factory reset it and everything

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Need Buying Advice For Smartphone Under ₹7000....:-D....Anybody Help....!

Hi Friends. I m Lucky Wamanker. I want some buying advice from u guys about buying a smartphone. First of all i tell u my budget us ₹7000 and i cant increase it more than ₹7200. My basic requirements are ::--
1.Minimum 1 gig of RAM.
2.Quadcore Processor.
3.Decent GPU.
I want this gadget primarily for gaming and web browsing. And i dont want any suggestion for xiomi or yu or any brand that has no service center in Indore. And again i tell u i want this smartphone for gaming.
I have found some by myself. Tell me about whuch is best ::--
1.Nokia Lumia 638
2.ZTE grand quad lite
3.ZTE grand x2
4.Huawei Honor Holly/Bee
5.Lenovo A6000
6.Xolo Omega 5.0
And i dont care whether it is Windows or Android. Or Internal Storage. And i want to play games like Nfs, Asphalt 8 abd Modern Combat 4.

Please suggest which one is best :

Hi,
I want to buy a smartphone with good specification under 20K.
Please suggest which one is best :
1). Samsung E7
2). ZTE Nubia Z9
3). HTC Desire 820S
4). Lenovo K80

Best Mobile to Buy this DEC under 15000

Hi There,

Could you please help select best mobile under 15000. I can wait couple of weeks if any new coming worth a wait. Games, fitness app and OSMAND map are my key stuff.

Saw couple of forum seems front runner is Moto 2nd gen and ZTE GRAND S II.

Motorola is released on sep(kind of old :-)) ZTE don't have latest OS.

Thanks.