Recent changes to the computer industry have brought out subtle changes to all sorts of electronics. Here are a few tables that might make you a better shopper:
USB Specifications
| USB Version | Maximum Speed | Color of Ports | Number of Wires |
|---|---|---|---|
| USB 1.1 | 12 Mbps | White | 4 |
| USB 2.0 | 480 Mbps | Black | 4 |
| USB 3.0 | 5 Gbps | Blue | 9 |
| USB 3.1 | 10 Gbps | Teal | 9 |
| USB 3.2 | 20 Gbps | Teal/Blue | 9 |
| USB4 | 40 Gbps | Teal/Black | 24 |
So be aware, if you buy a 3.0 flash drive (625 Mbps) and plug it into an old USB 1.1 slot, you will only get a maximum of 12 Mbps copy speed when you try to move a file into it. The color of the port is a help, but not a guarantee of the port speed. Some manufacturers ignore the scheme.
USB 2.0 and 3.0 connectors look like they only have 4 and 5 pins respectively, but inside the 3.0 connector the pins are cleverly connected to multiple wires to give additional throughput.
- 4 pins for USB 2.0 compatibility (4 wires: ground, power, and two data lines)
- 5 pins for USB 3.0 (5 more wires: two pairs for differential data transmission and an additional ground; some pins have multiple purposes, multiple wires connected)
- USB 4 connector has 24 pins, and a USB 4 cable typically contains 20 wires, capable of NVME speeds using an external drive. The speed bottleneck will be the drive itself, not the cable.
Different Types of Drives and Their Speeds
| Drive Type | Maximum Speed |
|---|---|
| HDD (Hard Disk Drive)* | ~160 MB/s |
| SATA SSD (Solid State Drive)** | 550 MB/s |
| NVMe SSD (Non-Volatile Memory Express) | 3,500 MB/s |
| USB 2.0 Flash Drive | 60 MB/s |
| USB 3.0 Flash Drive | 625 MB/s |
| Thunderbolt 3 SSD | 5,000 MB/s |
Comparison of Advertised vs. Real-World Speeds
| Interface | Advertised Speed | Real-World Speed |
|---|---|---|
| SATA I (1.5Gbps) | 1.5Gbps (150MB/s) | 120–130MB/s |
| SATA II (3Gbps) | 3Gbps (300MB/s) | 250–270MB/s |
| SATA III (6Gbps) | 6Gbps (600MB/s) | 550–600MB/s |
| USB 2.0 | 480Mbps (60MB/s) | 35–40MB/s |
| USB 3.0 / 3.1 Gen 1 | 5Gbps (625MB/s) | 400–450MB/s |
| USB 3.2 Gen 2 | 10Gbps (1.25GB/s) | 800–900MB/s |
| USB 3.2 Gen 2×2 | 20Gbps (2.5GB/s) | 1.8–2.2GB/s |
| USB4 / Thunderbolt 3 & 4 | 40Gbps (5GB/s) | 3–4GB/s |
| NVMe PCIe Gen 3×4 | 32Gbps (4GB/s) | 3–3.5GB/s |
| NVMe PCIe Gen 4×4 | 64Gbps (8GB/s) | 7–7.5GB/s |
Key Takeaways
- SATA speeds have doubled with each major revision, but real-world speeds are always lower due to protocol overhead. Manufacturers fail to factor in the additional overhead required to move data.
- SATA III (6Gbps) is still widely used, but NVMe PCIe drives have far surpassed SATA speeds.
- USB speeds have improved dramatically, but USB 2.0 is still much slower than even SATA I.
- USB 3.2 and is however now about 4x faster than Sata III.
- Thunderbolt 4 and USB4 offer speeds comparable to NVMe, making them ideal for high-speed external storage.
Central Processor Units
| CPU Type | Typical Speed Range | What It Means |
|---|---|---|
| Single-Core CPU | 1-2 GHz | Basic tasks (e.g., browsing, emailing) |
| Dual-Core CPU | 2-4 GHz | Multitasking (e.g., running several apps) |
| Quad-Core CPU | 2.5-4.5 GHz | Moderate gaming, video editing |
| Hexa-Core CPU | 3-5 GHz | Heavy multitasking, advanced gaming |
| Octa-Core CPU | 3.5-5.5 GHz | Professional video editing, 3D rendering |
| Deca-Core CPU | 4-6 GHz | High-end professional tasks, complex simulations |
Example with a 1GB File
- Single-Core: Think of it as having one person do the entire task alone.
- Dual-Core: Two people working together, splitting the task.
- Quad-Core: Four people, meaning quicker completion.
- Deca-Core: Ten people, so the task is done much faster.
And About that Internet….
| Wi-Fi Protocol | Maximum Speed | Frequency Band(s) |
|---|---|---|
| 802.11a | 54 Mbps | 5 GHz |
| 802.11b | 11 Mbps | 2.4 GHz |
| 802.11g | 54 Mbps | 2.4 GHz |
| 802.11n (Wi-Fi 4) | 600 Mbps (theoretical, unlikely) | 2.4 GHz / 5 GHz |
| 802.11ac (Wi-Fi 5) | 1.3 Gbps | 5 GHz |
| 802.11ax (Wi-Fi 6) | 10 Gbps | 2.4 GHz / 5 GHz |
| 802.11ax (Wi-Fi 6E) | 10 Gbps | 6 GHz, 5 GHz, 2.4 GHz |
Or if you prefer to be directly wired in:
| Cable Type | Maximum Speed | Distance Limit |
|---|---|---|
| Cat 5 | 100 Mbps | 100 meters |
| Cat 5e | 1 Gbps | 100 meters |
| Cat 6 | 1 Gbps | 100 meters |
| Cat 6a | 10 Gbps | 100 meters |
| Cat 7 | 10 Gbps | 100 meters |
| Cat 8 | 25-40 Gbps | 30 meters |
| Fiber Optic (single-mode) | Up to 100 Gbps | 40 kilometers or more |
| Fiber Optic (multi-mode) | Up to 100 Gbps | 550 meters |
A quick note here – notice that even at the lowest Cat 5, you are typically exceeding the Internet bandwidth offered by many Internet Service Providers, which is often 25Mbps or so.
Finally, here is a table to give you a realistic idea of what bandwidth you actually need:
Minimal Throughput Requirements for Home Devices
| Device | Minimal Throughput Requirement |
|---|---|
| HD TV (Streaming) | 5-10 Mbps |
| Roku (HD Streaming) | 3-5 Mbps |
| Wi-Fi Telephone Call | 1-2 Mbps |
| Security Camera | 2-3 Mbps (upload) |
| Internet-Viewable Security Camera | 5-10 Mbps (upload) |
| YouTube on Phone/Tablet | 1.5-4 Mbps (480p-1080p) |
Now remember, if you have 3 TVs and 6 family members streaming games or videos, multiply appropriately!
To sum it all up, if you are buying a computer, look for as many processors as you can afford, with USB 3 connectors, and an SSD or NVME drive if affordable. Very few people use more than 10% of a 1TB drive, so consider 256 to 512 GB drive size if it lowers cost. If you do have high speed Internet (greater than 100 Mbps) be sure that your the WiFi connection offers 802.11ac (WiFi 5) or 802.11ax (Wifi 6) protocol speeds, or be content with wiring your laptop to the router directly or you’ll likely get at most 30 Mbps. Likewise, the routers also must be capable of the WiFi 5 or better, else it is still best to wire them in directly (the wired ports generally connect at the maximum available speed (100 Mbps to 1000 Mbps) while wireless radios often broadcast in a range from 10 to 300 Mbps).
Memory Types and Their Speeds
| Memory Type | Data Transfer Rate (MT/s) | Typical Bandwidth (GB/s) | Description |
|---|---|---|---|
| DDR3 | 800-2133 MT/s | 6.4-17 GB/s | Older standard, still in use in many systems |
| DDR4 | 1600-3200 MT/s | 12.8-25.6 GB/s | Common in modern PCs and laptops |
| DDR5 | 3200-6400+ MT/s | 25.6-51.2+ GB/s | Latest standard, higher performance and efficiency |
| LPDDR4 | 1600-4266 MT/s | 12.8-34.1 GB/s | Low power version, used in mobile devices |
| LPDDR5 | 3200-6400+ MT/s | 25.6-51.2+ GB/s | Low power, high performance, used in newer mobile devices |
| GDDR5 | 6000-8000 MT/s | 192-256 GB/s | Used in graphics cards |
| GDDR6 | 12000-16000 MT/s | 384-512 GB/s | Newer graphics card memory with higher bandwidth |
| HBM2 (High Bandwidth Memory) | 2000 MT/s per pin | 256-512 GB/s | Used in high-end GPUs and accelerators |
