ESP32-WROVER vs WROOM: Understanding pSRAM, Advantages, Disadvantages & SDRAM Inclusion

I am thinking of buying to roughly touch some ESP8266 or ESP32 module. I am reading this page:
https://en.wikipedia.org/wiki/ESP32
and I see that the WRover differ from WROOM in that they have pSRAM

I have not found a Polish explanation of what pSRAM is, except for descriptions that it is Pseudo Dynamic and refreshed less frequently. If it's the same and can be refreshed less frequently, is it only better? Any other disadvantages?

And the second question in this layout comparison table for WROOM is only the size of the Flash memory. And yet SDRAM, some must have?

JanuszKornas wrote:

I have not found a Polish explanation of what pSRAM is

It's probably best to start with documentation producer's. I don't think there is any Polish yet ;)

JanuszKornas wrote:

And yet SDRAM, some must have?

Yes, SRAM. In documentation manufacturer for ESP-WROOM-02 says:

The RAM is in the ESP32 chip and all modules have the same, FLASH and PSRAM are separate silicon cubes "stuck" to the SPI, so their size is given, because they can be different.

khoam wrote:

Yes, SRAM. The manufacturer's documentation for ESP-WROOM-02 says:

this is just from a completely different story.

kaczakat wrote:

this is just from a completely different story.

In fact it should be (for ESP32-WROOM-32):

o 520 KB of on-chip SRAM for data and instructions.

Quote:

I have not found a Polish explanation of what pSRAM is

PSRAM is dynamic memory with internal refreshing logic so from the outside it can be treated as static SRAM (hence the name pseudo static ram). Why such inventions? Because you can connect large memories quite cheaply. SRAM is expensive. DRAM is cheap. PSRAM is more expensive than DRAM but cheaper than SRAM.