[FPGAs](https://www.ampheo.com/c/fpgas-field-programmable-gate-array) feel “low memory” because the memory you get on the FPGA chip itself is optimized for fast, parallel hardware work, not for storing lots of data like a CPU/[SoC](https://www.ampheo.com/c/system-on-chip-soc).


Here’s what drives that.

**1) Silicon area: SRAM is expensive, and FPGA logic is already “overhead-heavy”**

* On-chip FPGA memory is almost always SRAM blocks (BRAM/URAM).
* SRAM takes a lot of die area, and an FPGA already spends huge area on programmable routing + configuration bits (the “reconfigurable tax”).
So vendors can’t pack smartphone-style memory sizes without the chip becoming enormous and expensive.

**2) FPGA memory is built for bandwidth, not capacity**

BRAM/URAM is designed to give you:

* Many independent ports (often dual-port)
* Lots of parallel accesses
* Predictable single-digit-cycle latency

That’s perfect for FIFOs, line buffers, [filter](https://www.onzuu.com/category/filters) taps, caches, packet buffers… but it’s not meant to hold gigabytes.

**3) More on-chip RAM would also hurt timing, power, and yield**

* Bigger dies → worse manufacturing yield → higher cost
* More SRAM arrays → higher leakage and dynamic power
* Longer wires across the chip → harder timing closure
So vendors choose a balanced amount of BRAM so the device is usable and affordable.

**4) Most FPGA applications stream data, so they don’t need huge on-chip storage**

A lot of FPGA workloads are:

* video processing pipelines
* networking packet processing
* [ADC](https://www.onzuu.com/category/analog-to-digital-converters)/[DAC](https://www.onzuu.com/category/digital-to-analog-converters) [DSP](https://www.ampheo.com/c/dsp-digital-signal-processors) chains
* motor control / industrial I/O

These are streaming: data comes in, is processed in a pipeline, and goes out. You typically need buffers, not massive storage.

**5) “Big memory” is usually external (DDR/HBM/QSPI), not inside the FPGA fabric**

FPGAs scale memory by attaching:

* DDR3/DDR4/DDR5 (common on boards)
* HBM on high-end FPGAs (very high bandwidth, still not “free”)
* QSPI flash for configuration / logs (slow, cheap)

So the chip’s internal BRAM is like L1/L2 scratchpad, and external DDR/HBM is the “real RAM.”

**6) You can build larger memory out of logic, but it’s inefficient**

Using LUTs as RAM (distributed RAM) is great for small tables, but for large arrays it burns logic and routing quickly—another reason it “feels” limited.

**Mental model (helps a lot)**

* MCU/CPU: lots of RAM, runs instructions sequentially
* [FPGA](https://www.ampheoelec.de/c/fpgas-field-programmable-gate-array): less on-chip RAM, but can do many operations in parallel and move data with massive bandwidth