okay. but why price differ between them bcz of the longer duration or brand make the ram faster than other
Price will mainly be based on speed and timings, faster ram will generally be more expensive. But you have to consider timings as well, for example a 3000mhz CL14 kit would likely be more expensive than a 3200mhz CL16 kit. Also aesthetics, if you want ram covered in RGB LEDs or some kind of fancy heatsink you will pay for it.
If you find some G skill ram with the same speed and timings as some PNY ram and one is more expensive than the other, I do not think its worth paying a premium for a specific brand as long as its reputable like both PNY and g skill are.
There is no best RAM vendor. Most vendors such as G SKILL, PNY, Corsair, etc just take RAM IC modules from say SK Hynix or samsung slap them on a PCB and add a heat spreader. The "best" RAM in terms of perfomance would objectively be the fastest sticks with the lowest timings you can find regardless of the vendor, that tends to be ram using samsung B die IC's.
okay. but why price differ between them bcz of the longer duration or brand make the ram faster than other
Price will mainly be based on speed and timings, faster ram will generally be more expensive. But you have to consider timings as well, for example a 3000mhz CL14 kit would likely be more expensive than a 3200mhz CL16 kit. Also aesthetics, if you want ram covered in RGB LEDs or some kind of fancy heatsink you will pay for it.
If you find some G skill ram with the same speed and timings as some PNY ram and one is more expensive than the other, I do not think its worth paying a premium for a specific brand as long as its reputable like both PNY and g skill are.