为了尽可能地控制产品的体积和重量，ThinkPad X300采用了英特尔刚刚推出的小尺寸封装的Core 2 Duo L7100处理器，拥有1.2GHz主频的它，足以满足日常的办公需求，但是在3D图形应用方面就显得有些力不从心了。配合集成的X3100显卡，在半条命2中低画质下也难以流畅，但是对于定位商务的X300来说，足够轻才是最重要的。
由于配备了SSD固态硬盘，因此ThinkPad在磁盘性能方面有了很大的提升，从按下电源开关到进入Windows系统仅需27-32秒，比上一代的X61缩短了一半时间。
下面是ThinkPad的测试成绩：
| Notebook / CPU | wPrime 32M time |
| Lenovo ThinkPad X300 (Intel Core 2 Duo L7100 @ 1.20GHz) | 118 seconds |
| Apple MacBook Air (Intel Core 2 Duo P7500 @ 1.6GHz) |
68 seconds |
| Asus Eee PC 701 4G (Intel Celeron M ULV @ 900MHz) | 200 seconds |
| Sony VAIO TZ (Intel Core 2 Duo U7600 @ 1.20GHz) | 76 seconds |
| Dell XPS M1330 (Intel Core 2 Duo T7250 @ 2.20GHz) | 38 seconds |
| Notebook | PCMark05 Score |
| Lenovo ThinkPad X300 (Intel Core 2 Duo L7100 @ 1.20GHz, Intel X3100) | 3,467 PCMarks |
| Apple MacBook Air (1.6GHz Intel Core 2 Duo P7500, Intel X3100) |
2,478 PCMarks |
| Sony VAIO NR (1.5GHz Intel Core 2 Duo T5250, Intel X3100) | 3,283 PCMarks |
| Sony VAIO TZ (1.20GHz Core 2 Duo U7600, Intel GMA 950) | 2,446 PCMarks |
| Lenovo ThinkPad X61 (2.0GHz Intel Core 2 Duo T7300, Intel X3100) | 4,153 PCMarks |
| Lenovo 3000 V200 (2.0GHz Intel Core 2 Duo T7300, Intel X3100) | 3,987 PCMarks |
| Lenovo T60 Widescreen (2.0GHz Intel T7200, ATI X1400 128MB) | 4,189 PCMarks |
| HP dv6000t (2.16GHz Intel T7400, NVIDA GeForce Go 7400) | 4,234 PCMarks |
| Fujitsu N6410 (1.66GHz Core Duo, ATI X1400) | 3,487 PCMarks |
| Alienware M7700 (AMD Athlon FX-60, Nvidia Go 7800GTX) | 5,597 PCMarks |
| Sony VAIO SZ-110B in Speed Mode (Using Nvidia GeForce Go 7400) | 3,637 PCMarks |
| Asus V6J (1.86GHz Core Duo T2400, Nvidia Go 7400) | 3,646 PCMarks |
由于苹果MacBook Air没有配备SSD硬盘，所以出现了在wprime领先X300，但是在pcmark05中的成绩落后于X300。显然SSD硬盘表现出了超越5400rpm硬盘的性能。
ThinkPad X300磁盘表现
